WO2017014033A1 - Capteur de gaz de type à courant limite - Google Patents

Capteur de gaz de type à courant limite Download PDF

Info

Publication number
WO2017014033A1
WO2017014033A1 PCT/JP2016/069736 JP2016069736W WO2017014033A1 WO 2017014033 A1 WO2017014033 A1 WO 2017014033A1 JP 2016069736 W JP2016069736 W JP 2016069736W WO 2017014033 A1 WO2017014033 A1 WO 2017014033A1
Authority
WO
WIPO (PCT)
Prior art keywords
gas sensor
limiting current
current type
film
type gas
Prior art date
Application number
PCT/JP2016/069736
Other languages
English (en)
Japanese (ja)
Inventor
俊輔 赤坂
Original Assignee
ローム株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ローム株式会社 filed Critical ローム株式会社
Priority to JP2017529532A priority Critical patent/JP6730280B2/ja
Publication of WO2017014033A1 publication Critical patent/WO2017014033A1/fr

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/41—Oxygen pumping cells

Definitions

  • This embodiment relates to a limiting current type gas sensor.
  • a resistance change type a capacitance change type, a zirconia (ZrO 2 ) solid electrolyte type, and the like are known as humidity sensors for detecting the concentration of water vapor in a gas to be measured.
  • ZrO 2 zirconia
  • the resistance change type using a polymer film is inexpensive and has the advantage of being easy to make a device.
  • the measurement accuracy in the low humidity region is low and the temperature dependency is large.
  • the capacity change type has the advantages of good linearity, measurement in the entire relative humidity range, and low temperature dependence.
  • the capacity at a humidity of 0% RH is several hundred pF
  • the capacity change when 1% RH changes is 1 pF or less, and periodic calibration is required for accurate humidity measurement. It is an effective device when the accuracy of humidity measurement is not required in a general office environment, but it can be used for high-precision humidity measurement, condensation, and gas exposure (atmosphere observation applications and bathrooms), 100 ° C. Use in an atmosphere with such a high temperature is unexpected.
  • Humidity sensors using a zirconia solid electrolyte are sold for measuring humidity at high temperatures.
  • Oxygen sensor using the zirconia solid electrolyte is used for the reduction of the combustion efficiency and NO x of the motor vehicle, a track record in the durability as a material.
  • zirconia is used after being raised to several hundred degrees Celsius, power consumption is as high as 100 W, and handling of high-temperature objects is difficult, so the market is limited to some industrial applications.
  • This type of limiting current oxygen sensor has the advantage of high reliability and good linearity.
  • the limiting current type gas sensor including the zirconia thin film limiting current type improvement and stabilization of the sensor characteristics are required. Further, in the limiting current type gas sensor including the zirconia thin film limiting current type, further improvement in response speed is required.
  • This embodiment provides a limiting current type gas sensor that can improve the sensor characteristics and further stabilize the sensor characteristics.
  • the present embodiment provides a limiting current type gas sensor that can improve the response speed.
  • a substrate, a heater disposed on the substrate via a first insulating layer, and a heater disposed on the heater via a second insulating layer take in the gas to be measured.
  • a gas introduction path, a lower electrode disposed on the gas introduction path, a solid electrolyte layer disposed on the lower electrode, and an upper electrode disposed on a surface of the solid electrolyte layer facing the lower electrode And a limiting current type gas sensor provided with a cavity portion formed substantially larger than the heater on the substrate.
  • a substrate, a heater disposed on the substrate via a first insulating layer, and a gas intake portion disposed on the heater via a second insulating layer A lower electrode disposed on the gas inlet, a solid electrolyte layer disposed on the lower electrode, and an upper electrode disposed on a surface of the solid electrolyte layer facing the lower electrode; A cavity portion formed substantially larger than the heater on the substrate, the gas intake portion including a gas introduction path for taking in a gas to be measured, and a columnar portion disposed on the gas introduction path;
  • a limiting current type gas sensor is provided.
  • the substrate, the porous electrode formed using the porous material on the substrate, and the upper surface portion of the porous electrode are formed using the solid electrolyte material.
  • a solid electrolyte layer, a particle mixing layer formed at an interface between the solid electrolyte layer and the porous electrode, in which the particles of the porous material and the particles of the solid electrolyte material are mixed, and the solid electrolyte layer There is provided a limiting current type gas sensor including at least a dense electrode disposed on a surface facing the particle mixed layer.
  • a gas diffusion path having a predetermined aspect ratio and introducing a gas to be measured toward the sensor portion.
  • a step of forming a heater on the substrate via the first insulating layer, and a gas intake disposed on the heater via the second insulating layer and taking in the gas to be measured A step of forming a gas introduction path with an inlet, a step of forming a lower electrode on the gas introduction path, a step of forming a solid electrolyte layer on the lower electrode, and the lower portion on the solid electrolyte layer
  • a method for manufacturing a limiting current gas sensor is provided which includes a step of forming an upper electrode on a surface facing an electrode and a step of forming a cavity portion substantially larger than the heater in the substrate.
  • a step of forming a heater on a substrate via a first insulating layer, a step of forming a lower electrode on the heater via a second insulating layer, and the lower portion A step of forming a solid electrolyte layer on the electrode, a step of forming an upper electrode on the surface of the solid electrolyte layer facing the lower electrode, and the second insulating layer on the heater, A method for manufacturing a limiting current gas sensor is provided, which includes a step of forming a gas introduction path for introducing a gas to be measured and a step of forming a cavity portion substantially larger than the heater in the substrate.
  • a step of forming a porous electrode using a porous material on a substrate, and particles of the porous material and a solid electrolyte at least partially on the porous electrode A step of forming a particle mixed layer in which particles of material are mixed, a step of forming a solid electrolyte layer using the solid electrolyte material on the porous electrode so as to cover at least the particle mixed layer, and the solid electrolyte. And a step of forming a dense electrode on at least a surface facing the particle mixed layer including the upper surface portion of the layer.
  • a step of forming an upper electrode on a surface of the solid electrolyte layer facing the porous electrode, and an upper layer portion of the insulating layer having a predetermined aspect ratio and directing a gas to be measured toward the sensor portion And a process for forming a gas diffusion path to be introduced is provided.
  • a step of forming an upper electrode on a surface of the solid electrolyte layer facing the porous electrode, and a gas diffusion path having a predetermined aspect ratio and introducing a gas to be measured toward the sensor portion there is provided a method of manufacturing a limiting current type gas sensor having a step of forming a lid surrounding the region of the sensor portion and attaching the lid on the substrate.
  • a sensor network system including any one of the above-described limiting current gas sensors is provided.
  • FIG. 1 A Typical plane pattern block diagram of the limiting current type gas sensor which concerns on 1st Embodiment
  • FIG. 7A is a schematic plan view showing one step of the method for manufacturing the limiting current gas sensor according to the first embodiment, and FIG.
  • FIG. 6B is a schematic cross-sectional structure diagram taken along the line IA1-IA1 in FIG.
  • FIG. 8A is a schematic plan view showing one step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 7B is a schematic cross-sectional structure diagram taken along the line IA2-IA2 of FIG.
  • FIG. 9A is a schematic plan view showing a step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 8B is a schematic cross-sectional structure diagram taken along the line IA3-IA3 in FIG.
  • FIG. 10A is a schematic plan view showing one step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 9B is a schematic cross-sectional structure diagram taken along the line IA4-IA4 in FIG.
  • FIG. 11A is a schematic plan view showing one step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 10B is a schematic sectional view taken along line IA5-IA5 in FIG.
  • FIG. 11A is a schematic plan view showing one step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 11B is a schematic sectional view taken along line IA6-IA6 in FIG.
  • FIG. 12A is a schematic plan view showing one step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 12A is a schematic plan view showing one step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 12B is a schematic cross-sectional structure diagram taken along the line IA7-IA7 in FIG.
  • FIG. 14A is a schematic plan view showing a step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 13B is a schematic cross-sectional structure diagram taken along the line IA8-IA8 in FIG.
  • FIG. 15A is a schematic plan view showing a step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 14B is a schematic cross-sectional structure diagram taken along the line IA9-IA9 in FIG.
  • FIG. 16A is a schematic plan view showing one step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 15B is a schematic sectional view taken along the line IA10-IA10 in FIG.
  • FIG. 17A is a schematic plan view showing one step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 16B is a schematic cross-sectional structure diagram taken along the line IA11-IA11 in FIG.
  • FIG. 18A is a schematic plan view showing a step of the method for manufacturing the limiting current gas sensor according to the first embodiment
  • FIG. 17B is a schematic cross-sectional structure diagram taken along the line IA12-IA12 in FIG.
  • FIG. 20 is a diagram illustrating an example of a method for forming the lightly doped polysilicon layer illustrated in FIG. 19, wherein (a) a schematic cross-sectional structure diagram illustrating a polysilicon layer forming step, and (b) a schematic diagram illustrating an impurity implantation step.
  • Cross-sectional structure diagram (c) A schematic cross-sectional structure diagram showing a patterning step. It is a figure which shows the structural example of the low concentration doped polysilicon layer shown in FIG. 19, Comprising: (a) 1st typical cross-section figure, (b) 2nd typical cross-section figure, (c) 3rd (D) 4th typical cross-section figure, (e) 5th typical cross-section figure. It is a figure which shows the structural example of the low concentration doped polysilicon layer shown in FIG. 19, Comprising: (a) 6th typical cross-section figure, (b) 7th typical cross-section figure, (c) 8th (D) 9th typical cross-section figure, (e) 10th typical cross-section figure.
  • FIG. 1 A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a third modification of the first embodiment, (b) a schematic diagram of a limiting current type gas sensor along the ID-ID line in FIG. FIG. (A) A schematic plane pattern configuration diagram of a limiting current gas sensor according to a fourth modification of the first embodiment, (b) a schematic diagram of a limiting current gas sensor along the IE-IE line in FIG. FIG. (A) A schematic bird's-eye view configuration diagram showing results when simulation is performed using the limiting current gas sensor shown in FIG. 24, and (b) a limiting current gas sensor according to a comparative example is used for in-plane temperature distribution.
  • the typical bird's-eye view block diagram which shows the result at the time of performing a simulation.
  • the results of simulation using the limiting current type gas sensor shown in FIG. 24 are compared with the results of simulation using the limiting current type gas sensor according to the comparative example.
  • FIG. FIG. 25 is a schematic characteristic diagram showing the relationship between the thickness of the lightly doped polysilicon layer and the in-plane temperature distribution of the limiting current type gas sensor shown in FIG. 24.
  • FIG. 4C is a schematic sectional view showing a sensor portion of a limiting current type gas sensor according to the third embodiment.
  • FIG. 4D is a schematic view showing a sensor portion of the limiting current type gas sensor according to the fourth embodiment.
  • Cross-sectional structure diagram (e) a schematic cross-sectional structure diagram showing a sensor part of a limiting current type gas sensor according to a fifth embodiment, and (f) a sensor part of a limiting current type gas sensor according to a sixth embodiment.
  • FIG. 1 A schematic plane pattern block diagram of the limiting current type gas sensor which concerns on 2nd Embodiment, (b) The typical cross-section figure of the limiting current type gas sensor which follows the IIA-IIA line
  • a schematic plane pattern configuration diagram of a limiting current type gas sensor according to a first modification of the second embodiment (b) a schematic diagram of a limiting current type gas sensor along the line IIB-IIB in FIG.
  • FIG. A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a second modification of the second embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line IIC-IIC in FIG. FIG.
  • FIG. (A) A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a third modification of the second embodiment, (b) a schematic diagram of a limiting current type gas sensor along the IID-IID line of FIG. 33 (a).
  • FIG. (A) The typical plane pattern block diagram of the limiting current type gas sensor which concerns on 3rd Embodiment, (b) The typical cross-section figure of the limiting current type gas sensor which follows the IIIA-IIIA line
  • FIG. 37 A schematic plan view showing one step of a method for manufacturing a limiting current type gas sensor according to a third embodiment, (b) a schematic cross-sectional structure diagram taken along line IIIA3-IIIA3 of FIG. 37 (a).
  • FIG. 37 A schematic plan view showing one step of a method for manufacturing a limiting current type gas sensor according to a third embodiment, (b) a schematic cross-sectional structure diagram taken along line IIIA3-IIIA3 of FIG. 37 (a).
  • FIG. 42 A schematic plan view showing one step of a method for manufacturing a limiting current type gas sensor according to a third embodiment, (b) a schematic cross-sectional structure diagram taken along line IIIA8-IIIA8 in FIG. 42 (a).
  • FIG. (A) A schematic plane pattern configuration diagram of a limiting current gas sensor according to a second modification of the third embodiment, (b) a schematic diagram of a limiting current gas sensor along the line IIIC-IIIC in FIG. 45 (a).
  • FIG. (A) A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a third modification of the third embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line IIID-IIID in FIG. 46 (a).
  • FIG. (A) A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a fourth modification of the third embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line IIIE-IIIE in FIG. 47 (a).
  • FIG. 1 A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a fifth modification of the third embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line IIIF-IIIF in FIG.
  • FIG. 1 A schematic plane pattern block diagram of limit current type gas sensor according to fourth embodiment, (b) Typical cross-sectional structure diagram of limit current type gas sensor along line IVA-IVA in FIG. 49 (a).
  • a schematic plane pattern configuration diagram of a limiting current gas sensor according to a first modification of the fourth embodiment (b) a schematic diagram of a limiting current gas sensor taken along line IVB-IVB in FIG. 50 (a).
  • FIG. 1 A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a fifth modification of the third embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line IIIF-IIIF in FIG.
  • FIG. 1 A schematic plane pattern block diagram of limit current type gas sensor according to fourth embodiment, (b) Typical cross-sectional
  • FIG. 1 A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a second modification of the fourth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the IVC-IVC line in FIG. 51 (a).
  • FIG. (A) A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a third modification of the fourth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the IVD-IVD line in FIG. 52 (a).
  • FIG. (A) A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a fourth modification of the fourth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the IVE-IVE line in FIG. 53 (a).
  • FIG. (A) A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a fifth modification of the fourth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line IVF-IVF in FIG. 54 (a).
  • FIG. (A) A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a sixth modification of the fourth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the IVG-IVG line in FIG. 55 (a).
  • FIG. (A) A schematic plane pattern configuration diagram of a limiting current gas sensor according to a seventh modification of the fourth embodiment, (b) a schematic diagram of a limiting current gas sensor along the IVH-IVH line in FIG. 56 (a).
  • FIG. 59 A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a first example of the fifth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line VA1-VA1 of FIG. 57 (a).
  • FIG. (A) A schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 57, (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the line VA2-VA2 of FIG. 58 (a).
  • FIG. 59 A schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 59, (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VB2-VB2 line of FIG. 60 (a). .
  • FIG. 61 (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VC2-VC2 line of FIG. 62 (a).
  • FIG. 62 (a) Schematic plane pattern configuration diagram of a limit current type gas sensor according to Modification 3 of the first example of the fifth embodiment, (b) Limit current type along the line VD1-VD1 in FIG. 63 (a) The typical cross-section figure of a gas sensor.
  • FIG. 65 A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a second example of the fifth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the VE1-VE1 line of FIG. 65 (a).
  • FIG. (A) A schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 65, (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VE2-VE2 line of FIG. 66 (a). .
  • A Typical plane pattern configuration diagram of limit current type gas sensor according to modification 1 of second example of fifth embodiment, (b) Limit current type along line VF1-VF1 of FIG. 67 (a) The typical cross-section figure of a gas sensor.
  • FIG. 67 A schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 67, (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the line VF2-VF2 in FIG. 68 (a). .
  • a schematic plane pattern configuration diagram of a limiting current gas sensor according to Modification 2 of the second example of the fifth embodiment, (b) a limiting current equation along the line VG1-VG1 in FIG. 69 (a) The typical cross-section figure of a gas sensor.
  • FIG. 70 (a). .
  • FIG. 73 A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a third example of the fifth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line VJ1-VJ1 in FIG. 73 (a).
  • FIG. (A) A schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 73, (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VJ2-VJ2 line of FIG. 74 (a). .
  • A Typical planar pattern configuration diagram of a limiting current type gas sensor according to Modification 1 of the third example of the fifth embodiment, (b) Limiting current type along the VK1-VK1 line of FIG.
  • FIG. 75 (a) The typical cross-section figure of a gas sensor.
  • a schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 75 (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VK2-VK2 line in FIG. 76 (a). .
  • a schematic plane pattern configuration diagram of a limiting current type gas sensor according to Modification 2 of the third example of the fifth embodiment, (b) a limiting current type along the VL1-VL1 line of FIG. 77 (a) The typical cross-section figure of a gas sensor.
  • FIG. 77 (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VL2-VL2 line of FIG. 78 (a). .
  • FIG. 81 A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a first example of the sixth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line VIA1-VIA1 in FIG. 81 (a).
  • FIG. (A) A schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 81, (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the line VIA2-VIA2 of FIG. 82 (a).
  • FIG. 83 (a) The typical cross-section figure of a gas sensor.
  • FIG. 85 (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VIC2-VIC2 line of FIG. 86 (a).
  • FIG. 86 (a) Schematic plane pattern configuration diagram of a limiting current type gas sensor according to Modification 3 of the first example of the sixth embodiment, (b) Limiting current type along the VID1-VID1 line in FIG. 87 (a) The typical cross-section figure of a gas sensor.
  • FIG. 1 A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a second example of the sixth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line VIE1-VIE1 in FIG. 89 (a).
  • FIG. (A) A schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 89, (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along line VIE2-VIE2 of FIG. 90 (a).
  • FIG. 91 (a) The typical cross-section figure of a gas sensor.
  • a schematic plane pattern configuration diagram of a limiting current gas sensor according to Modification 2 of the second example of the sixth embodiment, (b) a limiting current equation along the line VIG1-VIG1 in FIG. 93 (a) The typical cross-section figure of a gas sensor.
  • FIG. 95 (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VIG2-VIG2 line in FIG. 94 (a).
  • FIG. 97 A schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 97, (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VIJ2-VIJ2 line of FIG. 98 (a).
  • FIG. 99 (a) The typical cross-section figure of a gas sensor.
  • a schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 99 (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VIK2-VIK2 line in FIG. .
  • a schematic plane pattern configuration diagram of a limiting current type gas sensor according to Modification 2 of the third example of the sixth embodiment (b) a limiting current type along the VIL1-VIL1 line in FIG. 101
  • FIG. 101 (a) The typical cross-section figure of a gas sensor.
  • FIG. 101 (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VIL2-VIL2 line in FIG. .
  • FIG. 103 Schematic plane pattern configuration diagram of a limiting current type gas sensor according to Modification 3 of the third example of the sixth embodiment, (b) Limiting current type along the line VIM1-VIM1 in FIG. 103
  • FIG. 104 The typical cross-section figure of a gas sensor.
  • a schematic plane pattern configuration diagram showing another configuration of the limiting current type gas sensor shown in FIG. 103 (b) a schematic cross-sectional configuration diagram of the limiting current type gas sensor along the VIM2-VIM2 line of FIG. 104 (a). .
  • FIG. 5 is a schematic diagram showing a relationship between a YSZ temperature and time in a gas concentration detection operation in the limiting current type gas sensor according to the present embodiment.
  • the typical cross-section figure explaining the principle of operation of the limiting current type gas sensor concerning this embodiment.
  • FIG. 6 is a schematic explanatory diagram of current-voltage characteristics in the limiting current type gas sensor according to the present embodiment.
  • FIG 3 is a schematic cross-sectional view for explaining ion conduction in the limiting current type gas sensor according to the present embodiment.
  • the typical bird's-eye view structure (perspective view) which shows the lid
  • the typical bird's-eye view composition (perspective view) figure showing the main part of the package which stores the limiting current type gas sensor concerning this embodiment.
  • the typical block block diagram which shows the limiting current type gas sensor which concerns on this Embodiment.
  • FIG. 116 A Typical plane pattern block diagram of limiting current type gas sensor according to seventh embodiment
  • the typical cross-section figure which shows the principal part of the limiting current type gas sensor which concerns on 7th Embodiment.
  • FIG. 10 is a diagram for explaining basic characteristics of a Pt + YSZ particle mixed layer in a limiting current type gas sensor according to a seventh embodiment, and (a) a schematic diagram illustrating an example in which a Pt + YSZ particle mixed layer exists; b) For comparison, a schematic diagram illustrating a case where no Pt + YSZ particle mixed layer is present.
  • FIG. 10 is a schematic diagram illustrating a case where a Pt + YSZ particle mixed layer is present and a case where a Pt + YSZ particle mixed layer is present in order to explain basic characteristics of the Pt + YSZ particle mixed layer in the limiting current type gas sensor according to the seventh embodiment.
  • FIG. 1 Schematic plan view showing one step (No. 1) of the manufacturing method of the limiting current type gas sensor according to the eighth embodiment, (b) Schematic cross section taken along line IIB-IIB in FIG. 132 (a) Structural drawing.
  • A Schematic plan view showing one step (No. 2) of the manufacturing method of the limiting current type gas sensor according to the eighth embodiment, (b) Schematic cross section taken along line IIC-IIC in FIG. 133 (a) Structural drawing.
  • FIG. 135 (a) Structural drawing.
  • FIG. 135 (a) Structural drawing.
  • FIG. 138 (a) Schematic plan view showing one step (No. 7) of the manufacturing method of the limiting current type gas sensor according to the eighth embodiment,
  • A Schematic cross-sectional structure diagram showing one step (beam structure forming step) of the method for manufacturing a limiting current gas sensor according to the present embodiment, (b) of the method for manufacturing the limiting current gas sensor according to the present embodiment The typical section structure figure showing one process (another beam structure formation process).
  • A Layout diagram (top view) of the beam structure of the limiting current gas sensor according to the present embodiment, (b) A schematic cross-sectional structure diagram taken along line IIIA-IIIA in FIG. 148 (a).
  • A Typical plane pattern block diagram of limiting current type gas sensor according to tenth embodiment
  • A Schematic plan view showing one step (No. 1) of the method of manufacturing the limiting current type gas sensor according to the tenth embodiment, (b) Schematic cross section taken along line IB-IB in FIG. 150 (a) Structural drawing.
  • A Schematic plan view showing one step (No. 3) of the method of manufacturing the limiting current type gas sensor according to the tenth embodiment, (b) Schematic cross section along the ID-ID line in FIG. 152 (a) Structural drawing.
  • FIG. 158 (a) Structural drawing.
  • A Schematic plan view showing one step (No. 7) of the manufacturing method of the limiting current type gas sensor according to the tenth embodiment, (b) Schematic cross section taken along line IH-IH in FIG. 156 (a) Structural drawing.
  • A Schematic plan view showing one step (No. 8) of the method for manufacturing the limiting current type gas sensor according to the tenth embodiment,
  • A Schematic plan view showing one step (No. 9) of the manufacturing method of the limiting current type gas sensor according to the tenth embodiment, (b) Schematic cross section taken along line IK-IK in FIG. 158 (a) Structural drawing.
  • FIG. 111 Schematic plan view showing one step (No. 10) of the manufacturing method of the limiting current type gas sensor according to the tenth embodiment, (b) Schematic cross section taken along the line IL-IL in FIG. 159 (a) Structural drawing.
  • FIG. 162 (A) Typical plane pattern block diagram of limiting current type gas sensor according to eleventh embodiment, (b) Typical sectional structure diagram of limiting current type gas sensor taken along line IIA-IIA in FIG. 162 (a).
  • A Schematic plan view showing one step (No. 1) of the method of manufacturing the limiting current type gas sensor according to the eleventh embodiment, (b) Schematic cross section taken along line IIB-IIB in FIG. 163 (a) Structural drawing.
  • A Schematic plan view showing one step (No. 2) of the method of manufacturing the limiting current type gas sensor according to the eleventh embodiment, (b) Schematic cross section taken along line IIC-IIC in FIG. 164 (a) Structural drawing.
  • FIG. 169 (a) Structural drawing.
  • FIG. 171 (a) Structural drawing.
  • A Typical plane pattern block diagram of limit current type gas sensor according to twelfth embodiment, (b) Typical sectional structure diagram of limit current type gas sensor along line IIIA-IIIA in FIG. 174 (a).
  • A A schematic plan view showing one step (No. 1) of a method for manufacturing a limiting current type gas sensor according to the twelfth embodiment, (b) a schematic cross section taken along line IIIB-IIIB in FIG. 175 (a) Structural drawing.
  • A Schematic plan view showing one step (No. 2) of the manufacturing method of the limiting current type gas sensor according to the twelfth embodiment, (b) Schematic cross section taken along line IIIC-IIIC in FIG. 176 (a) Structural drawing.
  • FIG. 178 A schematic plan view showing one step (No. 3) of the method of manufacturing the limiting current type gas sensor according to the twelfth embodiment, (b) Schematic cross section taken along line IIID-IIID in FIG. 177 (a) Structural drawing.
  • FIG. 1 Schematic plan view showing one step (No. 11) of the manufacturing method of the limiting current type gas sensor according to the twelfth embodiment, (b) Schematic cross section taken along line IIIM-IIIM in FIG. 185 (a) Structural drawing.
  • A A schematic plane pattern configuration diagram of a limiting current gas sensor according to a first modification of the twelfth embodiment, (b) a schematic diagram of a limiting current gas sensor along the line IVA-IVA in FIG. 186 (a).
  • FIG. 187 (a) -The typical cross-section figure along IVB line.
  • A Schematic plan view showing one step (part 2) of the method of manufacturing the lid in the limiting current gas sensor according to the first modification of the twelfth embodiment, (b) IVC in FIG. 188 (a) -The typical cross-section figure along an IVC line.
  • A Schematic plan view showing one step (part 3) of the method of manufacturing the lid in the limiting current gas sensor according to the first modification of the twelfth embodiment, (b) IVD in FIG. 189 (a) -The typical cross-section figure along an IVD line.
  • FIG. 4 is a schematic cross-sectional structure diagram along the line IVE.
  • A Typical top view which shows 1 process (the 5) of the manufacturing method of the cover body in the limiting current type gas sensor which concerns on the 1st modification of 12th Embodiment,
  • IVF of FIG. 191 (a) -The typical cross-section figure along an IVF line.
  • A Schematic plan view showing one step (No.
  • FIG. 192 A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a second modification of the twelfth embodiment, (b) a schematic diagram of a limiting current type gas sensor along the line VA-VA in FIG. 193 (a).
  • FIG. (A) A schematic plane pattern configuration diagram of a limiting current type gas sensor according to a third modification of the twelfth embodiment, (b) a schematic drawing of a limiting current type gas sensor along the line VIA-VIA in FIG. FIG.
  • the direction from the lower electrode 28D side to the upper electrode 28U side in each drawing. Is defined as upward (upward), and the opposite is defined as downward (downward).
  • the direction from the porous electrode 5D side to the dense electrode 5U side in each drawing is defined as the upper side, and vice versa.
  • the perpendicular direction means a substantially vertical direction in a plan view with respect to the planar pattern of the limiting current type gas sensor.
  • the in-plane direction is substantially the same plane direction with respect to the plane pattern of the limiting current type gas sensor.
  • This embodiment is roughly classified into, for example, first to sixth embodiments according to the structure of the sensor portion SP of the limiting current type gas sensor.
  • the sensor portion SP of the limiting current type gas sensor according to the first embodiment includes a porous oxide film (porous film) serving as a gas introduction path for taking in the measurement gas GS, as schematically shown in FIG. ) 51, the lower electrode 28D disposed on the porous oxide film 51, the solid electrolyte layer 30 disposed so as to cover the porous oxide film 51 and the lower electrode 28D, and the solid electrolyte layer 30 facing the lower electrode 28D And an upper electrode 28U disposed on the surface.
  • a porous oxide film porous film serving as a gas introduction path for taking in the measurement gas GS, as schematically shown in FIG. ) 51
  • the lower electrode 28D disposed on the porous oxide film 51
  • the solid electrolyte layer 30 disposed so as to cover the porous oxide film 51 and the lower electrode 28D
  • the solid electrolyte layer 30 facing the lower electrode 28D
  • an upper electrode 28U disposed on the surface.
  • the sensor portion SP of the limiting current type gas sensor according to the second embodiment includes a porous Pt film (porous film) that serves as a gas introduction path for taking in the gas GS to be measured, as schematically shown in FIG. ) 61, the lower electrode 28D disposed on the porous Pt film 61, the solid electrolyte layer 30 disposed so as to cover the porous Pt film 61 and the lower electrode 28D, and the solid electrolyte layer 30 facing the lower electrode 28D And an upper electrode 28U disposed on the surface.
  • a porous Pt film porous film
  • the sensor portion SP of the limiting current type gas sensor according to the third embodiment is arranged on a gas diffusion path MP serving as a gas introduction path for taking in the gas to be measured GS, as schematically shown in FIG.
  • the sensor portion SP of the limiting current type gas sensor according to the fourth embodiment is arranged on a gas diffusion path MP serving as a gas introduction path for taking in the gas to be measured GS, as schematically shown in FIG.
  • the sensor portion SP of the limiting current type gas sensor includes a gas introduction path (not shown) for taking in the measurement gas GS and a gas introduction path.
  • the gas intake part 303 including the arranged columnar film (columnar part), the lower electrode 28D arranged on the gas intake part 303, and the gas intake part 303 and the lower electrode 28D are arranged to cover the gas intake part 303.
  • a solid electrolyte layer 30 and an upper electrode 28U disposed on the solid electrolyte layer 30 facing the lower electrode 28D are provided.
  • the sensor portion SP of the limiting current type gas sensor includes a gas introduction path (not shown) for taking in the measurement gas GS and a gas introduction path.
  • the gas intake unit 305 including the disposed porous film (columnar portion), the lower electrode 28D disposed on the gas intake unit 305, and the gas intake unit 305 and the lower electrode 28D are disposed to be covered.
  • the solid electrolyte layer 30 and the upper electrode 28U disposed on the solid electrolyte layer 30 facing the lower electrode 28D.
  • FIG. 1A A schematic plane pattern configuration of the limiting current type gas sensor 1A according to the first embodiment is expressed as shown in FIG. 1A, and a schematic diagram of the gas sensor 1A along the line IA-IA in FIG. The cross-sectional structure is expressed as shown in FIG.
  • the limiting current type gas sensor 1A has a MEMS (Micro Electro Electro Mechanical Systems) beam structure.
  • a micro heater MH, a sensor portion SP, heater connecting portions 21 and 22, terminal electrode connecting portions 23 and 24, and an opening 45 are provided on a substrate (for example, Si) 12 provided.
  • the sensor portion SP includes a porous oxide film (porous film) 51 disposed via a SiN film 201 on a substrate 12 corresponding to an active region (described later), and a lower electrode disposed on the porous oxide film 51.
  • a porous oxide film (porous film) 51 disposed via a SiN film 201 on a substrate 12 corresponding to an active region (described later), and a lower electrode disposed on the porous oxide film 51.
  • 28D a solid electrolyte layer 30 disposed so as to cover the porous oxide film 51 and the lower electrode 28D, and an upper electrode (for example, Pt film) 28U disposed on the solid electrolyte layer 30 facing the lower electrode 28D.
  • the porous oxide film 51 functions as a gas introduction path and has a gas intake 51G.
  • the lower electrode 28D can be formed, for example, with a thickness of about 100 nm by a Pt / Ti electrode that is a laminated film of a Pt film and a Ti film.
  • the Ti film is used to make the junction with the porous oxide film 51 dense and stronger.
  • the solid electrolyte layer 30 can be formed of a YSZ film having a thickness of about 1 ⁇ m. This is because if it is thin, the upper and lower electrodes 28U and 28D are electrically connected. For example, the solid electrolyte layer 30 is disposed so as to cover the periphery of the lower electrode 28D, and conduction between the upper and lower electrodes 28U and 28D is prevented.
  • the porous oxide film 51, the lower electrode 28D, the solid electrolyte layer 30, and the upper electrode 28U of the sensor portion SP are all rectangular. It may have a shape other than that.
  • the porous oxide film 51, the lower electrode 28D, the solid electrolyte layer 30, and the upper electrode 28U constituting the sensor portion SP are preferably arranged at the center of the sensor surface without being eccentric, but on the microheater MH. If present, they may be arranged in an eccentric state.
  • the heater connecting portions 21 and 22 are arranged so as to face each other in the left-right direction (in-plane direction along the cross section in FIG. 1B) centering on the sensor portion SP.
  • the heater connecting portion 21 has a connecting pad 211, a wiring portion 212, and a terminal portion 213, and the heater connecting portion 22 has a connecting pad 221, a wiring portion 222, and a terminal portion 223.
  • the terminal electrode connecting portions 23 and 24 are arranged so as to face the heater connecting portions 21 and 22 in the vertical direction in the figure, with the sensor portion SP as the center.
  • the terminal electrode connection part 23 has a connection pad (detection terminal) 231 and a wiring part 232, and the terminal electrode connection part 24 has a connection pad (detection terminal) 241 and a wiring part 242.
  • the heater connecting portions 21 and 22 and the terminal electrode connecting portions 23 and 24 are provided on the SiN film 201, and are formed by, for example, a laminated film (Pt / Ti laminated film) of a 20 nm thick Ti film and a 100 nm thick Pt film. can do.
  • a laminated film Pt / Ti laminated film
  • the terminal portions 213 and 223 of the heater connecting portions 21 and 22 are connected to the microheater MH, and the wiring portion 232 of the terminal electrode connecting portion 23 extends in the direction of the sensor portion SP and extends to the extending end 28D1 of the lower electrode 28D.
  • the wiring portion 242 of the terminal electrode connection portion 24 extends in the direction of the sensor portion SP and is connected to the extending end 28U1 of the upper electrode 28U.
  • a detection circuit for detecting a predetermined gas concentration in the gas to be measured by a limiting current type is connected to the connection pads 231 and 241 of the terminal electrode connection portions 23 and 24, a detection circuit for detecting a predetermined gas concentration in the gas to be measured by a limiting current type.
  • the detection circuit 107 is limited by supplying a detection voltage V to the upper electrode 105U and the porous electrode (porous electrode) 105D of the solid electrolyte layer 106.
  • the oxygen concentration can be detected based on the current.
  • the detection circuit 107 can detect the water vapor concentration based on the limit current.
  • the terminal portions 213 and 223 of the heater connecting portions 21 and 22 are covered with a SiN film 26 disposed so as to surround the outer peripheral portion of the sensor portion SP in plan view.
  • a SiO 2 film 25 is embedded between the SiN film 26 and the terminal portions 213 and 223.
  • the opening 45 has an active region and an inactive region corresponding to each corner of the substrate 12 outside the SiN film 26 and excluding the heater connecting portions 21 and 22 and the terminal electrode connecting portions 23 and 24 in plan view. It is arranged in an L-shape at the boundary part with (described later).
  • the opening 45 is opened when forming a cavity (Cavity) C having a boat-shaped structure, and may have a shape other than an L shape, such as a straight shape (I shape). good.
  • the microheater MH is provided between first and second insulating layers (for example, SiO 2 films) 181 and 182 constituting the insulating layer 18.
  • the microheater MH is, for example, a polysilicon layer (polysilicon heater) having a thickness of 0.2 ⁇ m, and B (boron), which is a p-type impurity, is highly concentrated (for example, 4 ⁇ 10 19 cm) by an ion implantation method. -3 ), the resistance value is about 300 ⁇ .
  • the thermal conductivity of the micro heater MH is desirably about 80 W / mK, for example.
  • the microheater MH is disposed, for example, in a rectangular shape below the solid electrolyte layer 30, and has a larger area than the solid electrolyte layer 30. It is desirable to form.
  • the microheater MH is for heating the solid electrolyte layer 30.
  • the microheater MH is not limited to being disposed between the first and second insulating layers 181 and 182 on the substrate 12 but may be disposed below the substrate 12 or embedded in the substrate 12. It may be. Alternatively, a structure in which a laminated film (not shown) of SiO 2 film / SiN film including the microheater MH made of polysilicon is formed on the surface of the substrate 12 may be adopted.
  • micro heater MH can be formed by a Pt heater formed by printing.
  • the micro heater MH but also a nano size heater can be used as long as it has a larger area than the sensor portion SP.
  • a boat-shaped cavity C connected to the opening 45 is formed on the substrate 12 below the microheater MH.
  • An insulating layer 16 made of a SiON film is provided at the interface between the cavity C and the first insulating layer 181 corresponding to the cavity C, and the interface between the substrate 12 and the first insulating layer 181 corresponding to the inactive region of the substrate 12.
  • the MEMS beam-structured substrate 12 has a thickness of about 10 ⁇ m, for example, and the cavity portion C is formed to be substantially larger than the microheater MH, thereby preventing heat from escaping from the membrane. ing.
  • the planar shape of the cavity portion C is not particularly limited, but it is desirable to form it in a square shape, like the sensor portion SP and the microheater MH.
  • the MEMS beam structure may be formed having an open structure (see FIG. 18) in which the substrate 12 is disposed so as to surround the sensor portion SP in plan view.
  • the cavity part C can also be made into the structure formed by bonding the board
  • the limiting current gas sensor 1A includes the substrate 12, the heater MH disposed on the substrate 12 via the first insulating layer 181 and the second insulating layer 182 on the heater MH.
  • the upper electrode 28U disposed on the surface facing the lower electrode 28D, and the cavity portion C formed substantially larger than the heater MH on the substrate 12 are provided.
  • the limiting current gas sensor 1A has a MEMS beam structure substrate 12 in which the cavity portion C has a boat-type structure, as shown in FIGS. 1 (a) and 1 (b).
  • the gas to be measured for example, O 2 gas
  • the gas to be measured is introduced into the solid electrolyte layer 30 of the sensor portion SP through the gas intake port 51G of the porous oxide film 51. It is configured. That is, the gas to be measured is taken into the porous oxide film 51 from the gas inlet 51G, introduced into the solid electrolyte layer 30 through the lower electrode 28D, and then diffused into the solid electrolyte layer 30 by heating.
  • the introduction of the measurement gas into the solid electrolyte layer 30 may involve a suction operation.
  • the limiting current type gas sensor 1A has a beam structure (boat type structure) having a MEMS structure as a basic structure, although it involves heating of the microheater MH.
  • the heat capacity is reduced to improve sensor sensitivity.
  • the gas inlet 51G can be integrally formed of the same material as that of the porous oxide film 51 so as to extend in a direction along the terminal electrode connection portion 23 in a plan view. Alternatively, the amount of gas to be measured can be changed by adjusting the width or the like.
  • the gas inlet 51G can be formed separately from the porous oxide film 51, and, for example, in a direction other than the direction along the terminal electrode connection portion 23 in the plan view, You may arrange
  • the heater connecting portions 21 and 22 are arranged in the horizontal direction, and the terminal electrode connecting portion 23 is arranged on the lower end side in the vertical direction so as to be orthogonal thereto.
  • the terminal electrode connection part 24 is respectively arrange
  • the method of forming the porous electrode is expressed as shown in FIGS. 2 (a) to 2 (c).
  • the porous electrode includes, for example, a porous oxide film 51 which is a nano-sized porous film, and a lower electrode 28D made of a Pt / Ti laminated film (Pt / Ti electrode) formed on the porous oxide film 51. Is done.
  • the porous electrode is first formed by, for example, YSZ containing 70 vol% to 50 vol% YSZ particles 511 and 30 vol% to 50 vol% SiO 2 512 on the substrate 120 by sputtering.
  • a SiO 2 film (porous forming film) 510 is formed.
  • a Pt / Ti laminated film is formed on the YSZ particles 511 in the porous oxide film 51 by, for example, a sputtering method, and the porous oxide film 51 and the lower electrode 28D are configured.
  • a porous electrode to be formed is formed.
  • the porous oxide film 51 can be easily formed by forming a YSZ-SiO 2 film 510 that is an oxide by sputtering and etching. In particular, it has high thermal stability and can form a hole with a diameter of about 10 nm, and is excellent in gas drawing performance.
  • the step of forming the porous oxide film 51 is not limited to the above example.
  • the porous film that includes Al 2 O 3, SiO 2, or YSZ and is sol-coated by spin coating is baked. Can also be formed.
  • the porous oxide film 51 is, for example, a porous film (Al 2 O 3 —SiO 2 film) containing 70 vol% Al 2 O 3 and 30 vol% SiO 2 , or 70 vol% YSZ and 30 vol% Al 2. O 3 and also by the porous formed film (YSZ-Al 2 O 3 film) to HF etching process comprising, it can be formed similarly.
  • the porous electrode may be made of a porous Pt film or a porous Pt / Ti film.
  • the current value is proportional to the temperature T to the ⁇ a power (current value ⁇ T ⁇ a ).
  • the a value can be adjusted by the porous film structure. That is, when the pore of the porous film is small, the value a increases.
  • the porous oxide film 51 Since the porous oxide film 51 is formed of a porous film having such temperature characteristics, it has temperature dependence, and the current value decreases as the temperature increases. That is, as shown in FIG. 3, as the porous oxide film 51 becomes higher in temperature, the distance Lnm (for example, 100 nm) at the center of the hole hardly changes, but the distance between both ends changes from HW to HS. . When the distance between both ends is reduced (HW> HS), the flow rate of the gas passing therethrough is limited and reduced, and as a result, the current value is lowered (current value ⁇ gas flow rate).
  • the relationship between the temperature T and the saturation current Isat ⁇ in the porous oxide film 51 is expressed as shown in FIG.
  • T1 ° C. eg, 400 ° C.
  • T2 ° C. eg, 450 ° C.
  • T3 ° C. eg, 500 ° C.
  • T4 ° C. eg, 700 ° C.
  • the current value is proportional to the temperature T about 0.5 to the power of Knudsen diffusion (current value ⁇ T 0.5 ), and the current value is normal diffusion. Is proportional to about 0.75 power of temperature T (current value ⁇ T 0.75 ). That is, in the case of the microchannel, as the temperature becomes higher, the flow rate of the passing gas increases, and the current value increases accordingly.
  • the heat capacity can be reduced by the cavity portion C, so that the sensor characteristics can be improved.
  • a schematic plane configuration of the wafer 100 applied to the manufacture of the limiting current type gas sensor 1A according to the first embodiment is expressed as shown in FIG. 5A, and is taken along line IA0-IA0 in FIG.
  • a schematic cross-sectional structure of the wafer 100 along the line is represented as shown in FIG.
  • the wafer 100 has a plurality of element regions 104 defined by the element isolation regions 102, and the element isolation regions 102 are formed in the final stage of the manufacturing process of the gas sensor 1A. Is diced along. Thereby, the wafer 100 is divided
  • WC1 indicates the width in the sectional direction of the formation region CA of the cavity portion C
  • WS1 indicates the width in the sectional direction of the formation region SA of the sensor portion SP
  • AA1 indicates the active region.
  • the width of AA in the cross-sectional direction is indicated
  • CA1 indicates the width of the element region 104 in the cross-sectional direction.
  • a portion excluding the active region AA from the element region 104 is a non-active region.
  • Si silicon as a semiconductor material
  • Pt platinum as a porous material
  • Ti titanium as an electrode material
  • YSZ solid.
  • Yttria-Stabilized Zirconia as electrolyte material.
  • the manufacturing method of the limiting current type gas sensor 1A includes the step of forming the heater MH on the substrate 12 via the first insulating layer 181 and the second insulating layer 182 on the heater MH.
  • the step of forming a gas introduction path 51 provided with a gas inlet 51G for taking in the gas to be measured, the step of forming the lower electrode 28D on the gas introduction path 51, and the solid on the lower electrode 28D A step of forming the electrolyte layer 30, a step of forming the upper electrode 28U on the surface of the solid electrolyte layer 30 facing the lower electrode 28D, and a cavity portion C substantially larger than the heater MH is formed on the substrate 12. The process of carrying out.
  • FIGS. 1 (a) and 1 (b) the manufacturing method of the limiting current type gas sensor 1A according to the first embodiment shown in FIGS. 1 (a) and 1 (b) is shown in FIGS.
  • FIGS. 6A and 6B First, as shown in FIGS. 6A and 6B, for example, element isolation regions 102 formed in a lattice shape along dicing lines on the surface of a Si wafer 100 having a thickness of 10 ⁇ m.
  • the insulating film is removed, and a surface 12a corresponding to the active region AA and a surface 12b corresponding to the other inactive regions are formed on the substrate 12.
  • the insulating film in the element isolation region 102 is removed by selective etching using, for example, a LOCOS (Local Oxidation of Silicon) technique.
  • LOCOS Local Oxidation of Silicon
  • the upper surface of the substrate 12 has a shape in which an inclined surface 12c is provided in a peripheral portion between the surface 12a corresponding to the active region AA and the surface 12b corresponding to the non-active region.
  • an SiO 2 film having a thickness of about 0.5 ⁇ m is formed on the upper surface of the substrate 12 by a CVD (Chemical Vapor Deposition) method or the like.
  • CVD Chemical Vapor Deposition
  • an insulating layer 16 made of a SiON film having a thickness of about 0.5 ⁇ m is uniformly formed on the upper surface of the substrate 12 by a plasma CVD (P-CVD) method or the like.
  • the insulating layer 14 may be formed by leaving a part of the insulating film in the element isolation region 102.
  • a first insulating layer 181 made of a SiO 2 film having a thickness of about 0.5 ⁇ m is formed on the insulating layer 16 by CVD or the like.
  • a polysilicon layer having a thickness of about 0.2 ⁇ m is formed on the upper surface by a low pressure CVD method or the like, and the polysilicon layer is patterned by etching or the like to form a micro heater MH having a tapered portion Ht.
  • the microheater MH is formed on the surface 12a corresponding to the active area AA, for example, with a size of about 300 ⁇ m square. Further, the microheater MH has a resistance value of 300 ⁇ by implanting B at a high concentration by an ion implantation (I / I) method.
  • a SiON film (second insulating layer) 182 having a thickness of about 0.5 ⁇ m is formed on the entire surface by P-CVD or the like.
  • the Pt / Ti laminated film is deposited by sputtering or the like so as to have a thickness of about 0.5 ⁇ m, and the Pt / Ti laminated film is formed.
  • the film is patterned by etching to form connection pads 211 and 221, wiring portions 212 and 222, and terminal portions 213 and 223 of the heater connection portions 21 and 22.
  • the SiO 2 film 25 is formed so as to fill the opening 37 by CVD or the like, and the SiN film 26 is formed.
  • the SiO 2 film 25 and the SiN film 26 are selectively etched and patterned so as to surround the sensor portion SP.
  • a porous oxide film 51 and a gas inlet 51G for taking in the gas to be measured are formed by sputtering and etching.
  • a lower electrode 28D made of a Pt / Ti laminated film having a thickness of about 100 nm is formed on the porous oxide film 51 by sputtering or the like.
  • the extension end 28D1 of the lower electrode 28D is connected to the wiring part 232 of the terminal electrode connection part 23.
  • a solid electrolyte layer 30 made of a YSZ film is formed by about 1 ⁇ m by sputtering so as to cover the porous oxide film 51 and the lower electrode 28D. The thickness is formed.
  • the solid electrolyte layer 30 covers the entire periphery of the porous oxide film 51 and the lower electrode 28D except for the extended end 28a of the lower electrode 28D.
  • a Pt film having a thickness of about 100 nm is formed on the surface facing the lower electrode 28D on the solid electrolyte layer 30 by sputtering as the upper electrode 28U.
  • the extension end 28U1 of the upper electrode 28U is formed and connected to the wiring part 232 of the terminal electrode connection part 24.
  • a mask 43 is formed on the entire surface (depot + patterning). Then, using the protective SiO 2 film 43 as a mask, the substrate 12 on the surface 12a corresponding to the active area AA is selectively deep-etched and etched to form a MEMS beam structure substrate 12 connected to the opening 45, which is about 400 ⁇ m square.
  • a cavity portion C having a boat-shaped structure is formed.
  • the limiting current gas sensor 1A according to the first embodiment having the configuration shown in FIGS. 1A and 1B is obtained. It is done.
  • the cavity portion C is formed to be substantially larger than the microheater MH, so that the heat capacity is reduced and the heating by the microheater MH causes the sensor periphery. It can be easily suppressed to spread unnecessarily.
  • the porous oxide film 51 has high thermal stability, the gas throttling performance is high. Moreover, the amount of gas to be measured can be easily controlled only by adjusting the size of the gas inlet 51G, and the limit current gas sensor 1A having excellent sensor characteristics can be obtained.
  • the gas diffusion path MP is not required due to the adoption of the porous oxide film 51, manufacturing is easy, and special equipment such as a high-pressure sputtering apparatus is not required, so that it can be manufactured at a lower cost. .
  • the limiting current type gas sensor according to the first embodiment the sensor characteristics can be easily improved, and the manufacture is easy and can be manufactured at a lower cost.
  • FIG. 18A A schematic plane pattern configuration of the limiting current type gas sensor 1B according to the first modification of the first embodiment is expressed as shown in FIG. 18A, and follows the line IB-IB in FIG. 18A.
  • FIG. 18A A schematic cross-sectional structure of the gas sensor 1B formed in the MEMS beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 1B is a MEMS beam structure having a cavity portion having an open structure in which the substrate 12 is disposed so as to surround the sensor portion SP in plan view. It may be formed with C.
  • the cavity C of the open structure can be easily formed by, for example, deeply etching the substrate 12 from the back side after forming the cavity C of the boat structure.
  • the limit current gas sensor 1B having excellent sensor characteristics can be obtained as in the case of the limit current gas sensor 1A described above.
  • FIG. 19A A schematic planar pattern configuration of a limiting current gas sensor 1C according to a second modification of the first embodiment is expressed as shown in FIG. 19A, and is along the IC-IC line of FIG. 19A.
  • FIG. 19A A schematic cross-sectional structure of the gas sensor 1C formed in the MEMS beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 1C according to the second modification of the first embodiment is designed to make the temperature uniform by increasing the thermal conductivity inside the membrane in the plane.
  • the thermal conductivity is high below the microheater MH.
  • the limiting current type gas sensor 1C according to the second modification of the first embodiment is configured such that a non-doped or lightly doped polysilicon layer (for example, 140 W / mK) 300 is inserted.
  • the lightly doped polysilicon layer 300 is low in impurity ions such as B, As (arsenic) or P (phosphorus) in the polysilicon layer. It is formed by doping or undoping to a concentration (for example, 10 18 / cm 3 or less).
  • lightly doped polysilicon layer 300 an example of a method for forming the lightly doped polysilicon layer 300 will be described with reference to FIGS.
  • the illustrated formation of the lightly doped polysilicon layer 300 is substantially in accordance with the steps shown in FIGS. 8A and 8B, for example.
  • a polysilicon layer 301 having a thickness of about 0.6 ⁇ m is formed on the upper surface of the first insulating layer 181 by, for example, a low pressure CVD method.
  • a low-concentration layer LC having a thickness of 0.4 ⁇ m is formed on the lower layer side of the polysilicon layer 301.
  • a high concentration layer HC having a thickness of 0.2 ⁇ m is formed on the upper layer side.
  • the polysilicon layer 301 is patterned by etching or the like to form a microheater MH composed of the high concentration layer HC having the heating area L1, and a low concentration having the same size as the heating area L1.
  • a lightly doped polysilicon layer 300 made of the layer LC is formed.
  • the lightly doped polysilicon layer 300 can be formed in various sizes and shapes as shown in FIGS. 21 (a) to 21 (e) and FIGS. 22 (a) to 22 (e). it can.
  • the lightly doped polysilicon layer 300 may have the same size as the microheater MH and the outer peripheral portion thereof may be formed in a tapered shape. As shown in FIG. 4, the outer peripheral portions may be formed in a vertical shape.
  • the lightly doped polysilicon layer 300 may be formed larger than the microheater MH as shown in FIG. 21C, or smaller than the microheater MH as shown in FIG. It may be formed.
  • the lightly doped polysilicon layer 300 may be formed in such a shape that the microheater MH is embedded in the surface so that the upper surfaces thereof are the same. As shown to 22 (a), you may form so that microheater MH may be accommodated in an inside.
  • the lightly doped polysilicon layer 300 may be formed so that a part of the microheater MH accommodated therein is exposed, as shown in FIG. In this way, the entire micro heater MH housed inside may be exposed.
  • lightly doped polysilicon layer 300 may be formed so as to be laminated on the upper and lower surfaces of the microheater MH as shown in FIG. 22D, or as shown in FIG. You may form so that the lower half of heater MH may be embedded.
  • the lightly doped polysilicon layer 300 is formed to a thickness of about 0.6 ⁇ m, for example, so that the thermal conductivity is 6.25 times that in the case where the lightly doped polysilicon layer 300 is not provided. it can.
  • the low-concentration doped polysilicon layer 300 has a high resistance, so that it does not affect the heater characteristics of the microheater MH, has better temperature characteristics, and has excellent sensor characteristics. It can be.
  • FIG. 23A A schematic plane pattern configuration of a limiting current type gas sensor 1D according to a third modification of the first embodiment is expressed as shown in FIG. 23A, and is along the ID-ID line in FIG.
  • FIG. 23A A schematic cross-sectional structure of the gas sensor 1D formed in the MEMS beam structure is expressed as shown in FIG.
  • the low-concentration doped polycrystal having high thermal conductivity is provided below the microheater MH.
  • the limiting current gas sensor 1D according to the third modification of the first embodiment is configured to insert the silicon layer 300.
  • FIG. 24A A schematic plane pattern configuration of the limiting current type gas sensor 1E according to the fourth modification of the first embodiment is expressed as shown in FIG. 24A, and is along the IE-IE line in FIG.
  • FIG. 24A A schematic cross-sectional structure of the gas sensor 1E formed in the MEMS beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 1E corresponds to each corner of the substrate 12 in plan view as shown in FIGS. 24 (a) and 24 (b).
  • the opening 45 to be arranged has an I shape.
  • the opening 45 is arranged so that each longitudinal direction is along each side of the substrate 12, and each short direction is arranged along one of the two sides in contact with each side of the substrate 12. Is done.
  • the gas sensor 1E performs porous oxidation on the frame portion 121 defined by the opening 45 on the substrate 12 and the central portion 33 supported by the arm portion 31 between the openings 45 with respect to the frame portion 121.
  • a sensor portion SP including the film 51, the lower electrode 28D, the solid electrolyte layer 30, and the upper electrode 28U, the SiN film 26, and the like are disposed.
  • the microheater MH and the low-concentration doped polysilicon layer 300 are provided inside the in-plane membrane.
  • the MEMS beam structure substrate 12 has an open structure in which a cavity portion C is formed corresponding to an in-plane membrane.
  • the central portion 33 and the arm portion 31 are provided along the longitudinal direction of the opening 45 in plan view, and one end of each side of the central portion 33 is supported by the arm portion 31. Therefore, in the connection part with the frame part 121 of the arm part 31, and the connection part with the center part 33, it can connect more firmly with respect to the deformation
  • a micro-heater (4 ⁇ 10 19 cm ⁇ 3 ) MH composed of a high-concentration layer HC having a thickness of 0.2 ⁇ m and a low-concentration doped polysilicon layer (1 ⁇ 10 18 cm) composed of a low-concentration layer LC having a thickness of 0.4 ⁇ m. ⁇ 3 or less)
  • the temperature uniformity of the limiting current type gas sensor 1E provided with 300 will be described.
  • the simulation result of the limit current type gas sensor 1E is expressed as shown in FIG. 25 (a), and for comparison, the limit of the comparative example including only the microheater MH composed of the high concentration layer HC having a thickness of 0.2 ⁇ m is shown.
  • the simulation result of the current type gas sensor 1F is expressed as shown in FIG. However, the actual gas sensors 1E and 1F were further simplified for the simulation.
  • the limiting current gas sensor 1E has a more uniform in-plane temperature than the limiting current gas sensor 1F. I was able to improve the sex.
  • FIG. 26 shows the relationship between the impurity concentration of B, As, and P in the lightly doped polysilicon layer 300 and the thermal conductivity.
  • the low-concentration doped poly having a thermal conductivity of about 140 W / mK.
  • a silicon layer 300 can be formed.
  • FIG. 27 shows a comparison between the temperature distribution in the plane of the limiting current type gas sensor 1E and the temperature distribution in the plane of the limiting current type gas sensor 1F.
  • FIG. 28 shows the relationship between the thickness of the low-concentration layer LC used for forming the low-concentration doped polysilicon layer 300 and the in-plane temperature distribution.
  • the in-plane temperature distribution is about 7%. It has been found that it can be improved over the limiting current type gas sensor 1F.
  • FIG. 30 (a) A schematic plane pattern configuration of the limiting current type gas sensor 2A according to the second embodiment is expressed as shown in FIG. 30 (a), and the MEMS beam structure along the IIA-IIA line in FIG. 30 (a) is shown.
  • a schematic cross-sectional structure of the gas sensor 2A provided is represented as shown in FIG.
  • the limiting current gas sensor 2A according to the second embodiment is configured such that the porous oxide film 51 of the limiting current gas sensor 1A described above is changed to a porous Pt film (porous film) 61. Since the other configuration is basically the same, redundant description will be omitted as much as possible, and the configuration of the characteristic part will be described in more detail.
  • the limiting current type gas sensor 2A has a MEMS beam structure substrate (for example, Si ) 12, a porous Pt film 61 as a gas introduction path disposed in the active area AA on the substrate 12, a lower electrode (Pt / Ti laminated film) 28D disposed on the porous Pt film 61, and a porous Pt A solid electrolyte layer (YSZ film) 30 disposed so as to cover the film 61 and the lower electrode 28D, and an upper electrode (for example, Pt film) 28U disposed on the solid electrolyte layer 30 facing the lower electrode 28D.
  • a MEMS beam structure substrate for example, Si 12
  • a porous Pt film 61 as a gas introduction path disposed in the active area AA on the substrate 12
  • a lower electrode (Pt / Ti laminated film) 28D disposed on the porous Pt film 61
  • a porous Pt A solid electrolyte layer (YSZ film) 30 disposed so as to cover the film 61
  • the limiting current type gas sensor 2A includes first and second insulating layers (for example, SiO 2 films) 181 and 182 on a rectangular substrate 12.
  • Gas to be measured for example, O 2 gas
  • the gas intake 61G of the porous Pt film 61 disposed on the SiN film 201 as the microheater MH is heated.
  • the gas to be measured is taken into the porous Pt film 61 from the gas inlet 61G instead of the porous oxide film 51, introduced into the solid electrolyte layer 30 through the lower electrode 28D, and then solidified by heating. It is diffused into the electrolyte layer 30.
  • the introduction of the measurement gas into the solid electrolyte layer 30 may involve a suction operation.
  • the gas inlet 61G can be integrally formed of the same material as that of the porous Pt film 61 so as to extend in a direction along the terminal electrode connection portion 23 in a plan view. Alternatively, the amount of gas to be measured can be changed by adjusting the width or the like.
  • the gas inlet 61G can also be formed separately from the porous Pt film 61, and in a plan view, other than the direction along the terminal electrode connection 23, for example, the direction along the terminal electrode connection 23 or You may arrange
  • the porous Pt film 61, the lower electrode 28D, the solid electrolyte layer 30, and the upper electrode 28U of the sensor portion SP are preferably arranged at the center of the sensor surface without any eccentricity, but the microheater MH If it is above, it may be arranged in an eccentric state.
  • porous Pt film 61 may be formed by sputtering and etching instead of the step of forming the porous oxide film 51 when manufacturing the above-described limiting current gas sensor 1A.
  • the cavity portion C is substantially larger than the micro heater MH as in the case of the limiting current type gas sensor 1A described above.
  • the porous Pt film 61 has high thermal stability, the gas throttling performance is high. Moreover, the amount of gas to be measured can be easily controlled by adjusting the size of the gas inlet 61G, and the limit current gas sensor 2A having excellent sensor characteristics can be obtained.
  • the gas diffusion path MP is not necessary, and thus the manufacturing is easy.
  • the limiting current gas sensor 2A can use the porous Pt film 61 as the lower electrode 28D, the Pt / Ti laminated film can be omitted.
  • the limiting current type gas sensor according to the second embodiment the sensor characteristics can be easily improved and can be easily manufactured.
  • FIG. 31A A schematic plane pattern configuration of the limiting current type gas sensor 2B according to the first modification of the second embodiment is expressed as shown in FIG. 31A, and is taken along the line IIB-IIB in FIG.
  • FIG. 31A A schematic cross-sectional structure of the gas sensor 2B formed in the MEMS beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 2B has an open-type cavity portion in which the substrate 12 is disposed so as to surround the sensor portion SP in a plan view as a MEMS beam structure. It may be formed with C.
  • the cavity C of the open structure can be easily formed by, for example, deeply etching the substrate 12 from the back side after forming the cavity C of the boat structure.
  • FIG. 32A A schematic plane pattern configuration of a limiting current type gas sensor 2C according to a second modification of the second embodiment is expressed as shown in FIG. 32A and is along the line IIC-IIC in FIG.
  • a schematic cross-sectional structure of the gas sensor 2C formed in the MEMS beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 2C according to the second modification of the second embodiment is configured to increase the thermal conductivity inside the membrane within the surface and to make the temperature uniform.
  • the thermal conductivity is high below the microheater MH.
  • the limiting current type gas sensor 2C according to the second modification of the second embodiment is configured such that a lightly doped polysilicon layer (for example, about 140 W / mK) 300 is inserted.
  • FIG. 33A A schematic planar pattern configuration of a limiting current gas sensor 2D according to a third modification of the second embodiment is expressed as shown in FIG. 33A, and is along the IID-IID line in FIG.
  • FIG. 33A A schematic cross-sectional structure of the gas sensor 2D formed in the MEMS beam structure is expressed as shown in FIG.
  • the limiting current gas sensor 2D according to the third modification of the second embodiment is configured to insert the silicon layer 300.
  • FIG. 34 (a) A schematic plane pattern configuration of the limiting current type gas sensor 3A according to the third embodiment is expressed as shown in FIG. 34 (a), and the MEMS beam structure along the line IIIA-IIIA in FIG.
  • FIG. 34 (a) A schematic cross-sectional structure of the gas sensor 3A provided is represented as shown in FIG.
  • the limiting current type gas sensor 3A according to the third embodiment is different from the limiting current type gas sensor according to the first and second embodiments described above in the configuration of the gas diffusion path, and other configurations. Are basically the same.
  • the limiting current type gas sensor 3A is a sensor on a substrate (for example, Si) 12 as shown in FIGS.
  • SiN films third and fourth insulating films 201 and 202 constituting the SiN layer 20, sensor portions SP, gas diffusion paths (gas introduction paths) MP gas inlets (openings) 47, SiN films 26, heater connection portions 21 and 22, terminal electrode connection portions 23 and 24, an opening 45, and the like.
  • the sensor portion SP covers the gas diffusion path MP disposed in the active region near the center on the substrate 12, the lower electrode (porous Pt / Ti film) 28D as a porous electrode, and the lower electrode 28D in plan view.
  • the substrate 12 (active region), the lower electrode 28D, the solid electrolyte layer 30, and the upper electrode 28U may all be square or other shapes.
  • the gas diffusion path MP is disposed below the lower electrode 28D via the SiN film 202.
  • the gas inlet 47 of the gas diffusion path MP has a plan view of the SiN film 26 in the active region corresponding to one direction of the sensor portion SP (for example, the left end in the direction along the cross section of FIG. 34B). Located in the vicinity.
  • the SiN film 26 is an outer peripheral portion of the sensor portion SP, and is disposed so as to surround the sensor portion SP in a square frame shape while maintaining a predetermined distance from the sensor portion SP.
  • openings 45 are arranged in an L shape outside the SiN film 26 and between the active region and the non-active region on the substrate 12 so as to correspond to each corner.
  • the opening 45 is formed when the cavity portion C having the boat structure is formed.
  • the opening 45 may have a shape other than the L shape, for example, a straight shape (I shape).
  • the pads 211 and 221 and the connection pads 231 and 241 of the terminal electrode connection portions 23 and 24 are arranged.
  • the connecting pads 211 and 221 are connected to the terminal portions 213 and 223 directly below the SiN film 26 via the wiring portions 212 and 222 drawn out in the direction of the sensor portion SP, respectively.
  • the connecting pad 231 is connected to the extended end 28D1 of the lower electrode 28D of the sensor part SP via the wiring part 232 drawn toward the sensor part SP, and the connecting pad 241 is connected to the sensor part SP. It is connected to the extended end 28U1 of the upper electrode 28U of the sensor portion SP through the wiring portion 242 drawn out in the direction.
  • a micro heater MH having a larger area than the sensor portion SP is provided between the first and second insulating layers (for example, SiO 2 films) 181 and 182 constituting the insulating layer 18 corresponding to the lower portion of the sensor portion SP.
  • a cavity portion (boat-shaped structure) C of the substrate 12 having a MEMS beam structure is formed below the microheater MH.
  • the gas to be measured (for example, O 2 gas) is introduced into the solid electrolyte layer 30 via the.
  • the gas to be measured is taken into the gas diffusion path MP immediately below the SiN film 202 from the gas intake 47 as the microheater MH is heated, passes through the gas flow path (micro flow path) 42, and the gas After being introduced into the solid electrolyte layer 30 from the lower electrode 28 ⁇ / b> D of the introduction port (opening) 41, it is diffused into the solid electrolyte layer 30.
  • the introduction of the measurement gas into the solid electrolyte layer 30 may involve a suction operation.
  • the lower electrode 28D and the solid electrolyte layer 30 are located on the side facing the gas intake port 47 (for example, the right end side in the direction along the cross section of FIG. 34B) of the side wall portion of the gas diffusion path MP. It is arranged so as to cover the part.
  • the lower electrode 28D is formed of a porous Pt / Ti film, which is a laminated film of a porous Pt film and a Ti film, for example, with a thickness of about 100 nm.
  • the Ti film is used to make the junction between the porous Pt film and the underlying SiN film 202 dense and stronger.
  • the lower electrode 28D is disposed so that a part thereof protrudes into the flow path 42 from the portion serving as the gas introduction port 41 of the gas diffusion path MP, and a metal particle sintered layer and a metal particle sintered layer described later. Have a fine gas introduction path (not shown).
  • the lower electrode 28D itself is formed in a nanostructure. That is, a sintered metal particle layer (dense Pt) in which Pt mixed with carbon nanotubes (CNT) is sintered and CNTs are finally burned to form a fine gas introduction path may be applied as the lower electrode 28D. Carbon nanoparticles may be applied instead of CNTs.
  • the fine gas introduction path in the lower electrode 28D can be formed by, for example, a heat treatment process of nanowires, nanotubes, nanoparticles, etc. having a nanometer scale contained in the metal particle sintered layer or an etching process combined with a heat treatment process. It is. Nanowires, nanotubes, and nanoparticles can be formed from, for example, carbon (C), zinc oxide (ZnO), and the like.
  • the metal particle sintered layer in the lower electrode 28D and the fine gas introduction path formed in the metal particle sintered layer will not be described in detail here, but the metal particle sintered layer includes nanowires.
  • the nanowire may comprise CNT or ZnO.
  • the metal particle sintered layer includes carbon nanotubes or carbon nanoparticles, and the fine gas introduction path is formed by burning the carbon nanotubes or carbon nanoparticles by burning the metal particle sintered layer in the atmosphere. May be.
  • the metal particle sintered layer may include ZnO, and the fine gas introduction path may be formed by etching ZnO by wet etching after burning the metal particle sintered layer in the atmosphere.
  • the metal particles of the metal particle sintered layer may include any one of Pt, Ag, Pd, Au, or Ru.
  • the metal particle sintered layer may include nanowires that are confined in the metal particle sintered layer and are not burned by combustion in the atmosphere.
  • the nanowire or nanoparticle has a diameter of about 0.1 ⁇ m or less.
  • the length of the nanowire is, for example, about 10 ⁇ m or less.
  • the merit of using the nanowire is that the gas permeation amount can be controlled by the shape (diameter and length) of the nanowire, and the gas permeation amount can be controlled by the ratio of the nanowire.
  • the limiting current type gas sensor 3A according to the third embodiment can control the gas permeation amount by the shape of the fine gas introduction path of the lower electrode 28D. Further, the limiting current type gas sensor 3A according to the third embodiment can control the gas permeation amount by the content ratio of the fine gas introduction path of the lower electrode 28D.
  • the solid electrolyte layer 30 is formed of a YSZ film having a thickness of about 1 ⁇ m. This is because if it is thin, the upper and lower electrodes 28U and 28D are electrically connected. For example, the solid electrolyte layer 30 is disposed so as to cover the periphery of the lower electrode 28D, and conduction between the upper and lower electrodes 28U and 28D is prevented.
  • the gas diffusion path MP is capable of controlling the flow rate of the gas to be measured according to the ratio of the channel length of the microchannel 42 from the gas inlet 47 for taking in the gas to be measured to the gas inlet 41 and the channel cross-sectional area.
  • the gas diffusion path MP may be arranged in an eccentric state with respect to the center of the sensor surface, and it is desirable that the gas inlet 41 is arranged near the center on the substrate 12 in plan view.
  • the lower electrode 28D, the solid electrolyte layer 30, and the upper electrode 28U may be stacked on the gas inlet 41 with the gas inlet 41 as the center. That is, the gas diffusion path MP, the lower electrode 28D, the solid electrolyte layer 30, and the upper electrode 28U constituting the sensor portion SP are decentered in different directions with respect to the center of the sensor surface as long as they are on the microheater MH. It may be arranged in a state.
  • the limiting current type gas sensor 3A according to the third embodiment can control the flow rate of the gas to be measured according to the aspect ratio of the gas diffusion path MP, and can improve the sensor characteristics by increasing the aspect ratio. By increasing the accuracy of formation of the diffusion path MP, the sensor characteristics can be further stabilized.
  • the MEMS beam-structured substrate 12 has a thickness of about 10 ⁇ m, for example, and the cavity portion C is formed to be substantially larger than the microheater MH, thereby preventing heat from escaping from the membrane. ing.
  • the MEMS beam structure may be formed to have an open structure (see FIG. 44) in which the substrate 12 is disposed so as to surround the sensor portion SP in a plan view. Moreover, the cavity part C can also be made into the structure formed by bonding the board
  • the limiting current gas sensor 3A has a beam structure (boat structure) having a MEMS structure as a basic structure, thereby reducing the heat capacity of the sensor portion SP and improving the sensor sensitivity. We are trying to improve.
  • the limiting current type gas sensor 3A includes the substrate 12, the heater MH disposed on the substrate 12 via the first insulating layer 181 and the second insulating layer 182 on the heater MH.
  • a gas introduction path MP that takes in the gas to be measured, a lower electrode 28D that is arranged on the gas introduction path MP, a solid electrolyte layer 30 that is arranged on the lower electrode 28D, and a solid electrolyte layer 30
  • the upper electrode 28U disposed on the surface facing the lower electrode 28D, and the cavity portion C formed substantially larger than the heater MH on the substrate 12 are provided.
  • the microheater MH is not limited to being disposed between the first and second insulating layers 181 and 182 on the substrate 12 which is the sensor portion SP. It may be disposed below the substrate 12 or may be embedded inside the substrate 12. Alternatively, a laminated film (not shown) of SiO 2 film / SiN film including the microheater MH formed of polysilicon may be formed on the surface of the substrate 12.
  • the manufacturing method of the limiting current type gas sensor 3A includes the step of forming the heater MH on the substrate 12 via the first insulating layer 181 and the second insulating layer 182 on the heater MH.
  • FIGS. 34 (a) and 34 (b) A manufacturing method of the limiting current type gas sensor 3A according to the third embodiment shown in FIGS. 34 (a) and 34 (b) is expressed as shown in FIGS.
  • the steps until the SiN film 201 having a thickness of about 0.5 ⁇ m is formed by the P-CVD method or the like shown in FIGS. 10A and 10B are the limit current according to the first embodiment. Since it is similar to the case of the gas sensor 1A, the subsequent steps will be described.
  • the flow path forming layer 35 is formed by using a film forming member having a different etching selectivity from the SiN films 201 and 202, for example, a polysilicon film.
  • the predetermined aspect ratio of the gas diffusion path MP can be easily increased by increasing the flow path length of the gas diffusion path MP or decreasing the cross-sectional area (flow path cross-sectional area) of the gas diffusion path MP.
  • the sensor characteristics can be improved by increasing the aspect ratio of the gas diffusion path MP.
  • SiN having a thickness of about 0.5 ⁇ m, which is different in etching selectivity from the flow path forming layer 35 over the entire surface by the P-CVD method or the like.
  • the SiN films 201 and 202 and the second insulating layer 182 are selectively etched to form the terminal portions 213 and 223 of the heater connecting portions 21 and 22 connected to the microheater MH.
  • the opening 37 is formed.
  • the Pt / Ti laminated film is deposited by sputtering to have a thickness of about 0.5 ⁇ m, and the Pt / Ti laminated film is formed.
  • the film is patterned by etching to form connection pads 211 and 221, wiring portions 212 and 222, and terminal portions 213 and 223 of the heater connection portions 21 and 22.
  • the heater connecting portions 21 and 22 and the terminal electrode connecting portions 23 and 24 are arranged so as to be orthogonal to each other.
  • the SiO 2 film 25 is formed so as to fill the opening 37 by CVD or the like, and the SiN film 26 is formed.
  • the SiO 2 film 25 and the SiN film 26 are selectively etched and patterned so as to surround the sensor portion SP.
  • the SiN film 202 on the flow path forming layer 35 is selectively etched and removed so that the flow path forming layer 35 is exposed.
  • An opening serving as a measurement gas introduction port 41 is formed.
  • a lower electrode 28D made of a porous Pt / Ti film having a thickness of about 100 nm is formed by sputtering or the like, and the lower electrode 28D is extended.
  • the end 28 ⁇ / b> D ⁇ b> 1 is connected to the wiring part 232 of the terminal electrode connection part 23.
  • a solid electrolyte layer 30 made of a YSZ film is formed with a thickness of about 1 ⁇ m by sputtering so as to cover the lower electrode 28D. To do.
  • the solid electrolyte layer 30 covers the entire periphery of the lower electrode 28D except for the extended end 28D1 of the lower electrode 28D.
  • a Pt film having a thickness of about 100 nm is formed on the surface facing the lower electrode 28D on the solid electrolyte layer 30 by sputtering as the upper electrode 28U.
  • the extension end 28U1 of the upper electrode 28U is formed and connected to the wiring part 242 of the terminal electrode connection part 24.
  • a mask 43 is formed on the entire surface (depot + patterning).
  • the substrate 12 is selectively deep-etched using the protective SiO 2 film 43 as a mask to form an opening 45, and A cavity portion C having a boat-type structure is formed as the substrate 12 having the MEMS beam structure.
  • the cavity C is preferably about 400 ⁇ m square so as to be substantially larger than the microheater MH, although it depends on the size of the limiting current type gas sensor 3A according to the third embodiment.
  • the SiN film 202 on the flow path forming layer 35 is further selectively removed by etching, and the gas to be measured is exposed so that the flow path forming layer 35 is exposed.
  • An opening to be the intake 47 is formed.
  • FIG. 34A and FIG. The limiting current type gas sensor 3A according to the third embodiment having the configuration shown in b) is obtained.
  • step of forming the gas diffusion path MP may be performed before the step of forming the cavity portion C, or may be performed simultaneously with the step of forming the cavity portion C.
  • the cavity portion C so as to be substantially larger than the microheater MH, it is possible to easily prevent the heating by the microheater MH from spreading unnecessarily to the sensor periphery as well as the heat capacity. it can.
  • the aspect ratio of the gas diffusion path MP can be easily increased by increasing the length of the micro flow path 42 of the gas diffusion path MP or decreasing the cross-sectional area.
  • the porous Pt / Ti film constituting the lower electrode 28D has high thermal stability, the gas throttling performance is high.
  • the limiting current type gas sensor according to the third embodiment, the sensor characteristics can be easily improved, and the sensor characteristics can be further stabilized.
  • FIG. 44 (a) A schematic plane pattern configuration of the limiting current type gas sensor 3B according to the first modification of the third embodiment is expressed as shown in FIG. 44 (a), and is taken along the line IIIB-IIIB in FIG. 44 (a).
  • FIG. 44 (a) A schematic cross-sectional structure of the gas sensor 3B formed in the MEMS beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 3B is an open-type cavity portion in which the substrate 12 surrounds the sensor portion SP in a plan view as a MEMS beam structure. It may be formed with C.
  • the cavity C of the open structure can be easily formed by, for example, deeply etching the substrate 12 from the back side after forming the cavity C of the boat structure.
  • the limiting current type gas sensor 3B capable of further stabilizing the sensor characteristics can be obtained.
  • FIG. 45A A schematic planar pattern configuration of a limiting current gas sensor 3C according to a second modification of the third embodiment is expressed as shown in FIG. 45A, and is taken along line IIIC-IIIC in FIG. 45A.
  • FIG. 45A A schematic cross-sectional structure of the gas sensor 3C formed in the MEMS beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 3C according to the second modification of the third embodiment is configured to increase the thermal conductivity in the membrane within the surface and to make the temperature uniform.
  • the thermal conductivity is high below the microheater MH.
  • a lightly doped polysilicon layer (for example, 140 W / mK) 300 is inserted in a limiting current type gas sensor 3C according to a second modification of the third embodiment.
  • FIG. 46A A schematic planar pattern configuration of a limiting current gas sensor 3D according to a third modification of the third embodiment is expressed as shown in FIG. 46A, and is taken along the line IIID-IIID in FIG. 46A.
  • FIG. 46A A schematic cross-sectional structure of the gas sensor 3D formed in the MEMS beam structure is expressed as shown in FIG.
  • the low-concentration doped poly-silicon having a high thermal conductivity below the micro heater MH in the structure of the limiting current type gas sensor 3B provided with the cavity C of the open type structure shown in FIGS. 44 (a) and 44 (b), the low-concentration doped poly-silicon having a high thermal conductivity below the micro heater MH.
  • the limiting current gas sensor 3D according to the third modification of the third embodiment is configured such that the silicon layer 300 is inserted.
  • FIG. 47 (a) A schematic planar pattern configuration of a limiting current type gas sensor 3E according to a fourth modification of the third embodiment is expressed as shown in FIG. 47 (a) and is along the line IIIE-IIIE in FIG. 47 (a).
  • FIG. 47 (a) A schematic cross-sectional structure of the sensor 3E in which the MEMS beam structure is formed in a boat-type structure is expressed as shown in FIG.
  • the limiting current type gas sensor 3E according to the fourth modification example of the third embodiment has, for example, a gas diffusion path of the sensor portion SP in plan view as shown in FIGS. 47 (a) and 47 (b).
  • the MP has two openings (a plurality of gas intake ports) 471 and 472.
  • the limiting current type gas sensor according to the fourth modification of the third embodiment the sensor characteristics can be easily improved, and the gas diffusion path can be formed more easily. Become.
  • the limiting current type gas sensor 3E it is easy to insert a low-concentration doped polysilicon layer 300 having high thermal conductivity under the microheater MH, or to form the MEMS beam structure in an open structure. .
  • FIG. 48A A schematic planar pattern configuration of a limiting current gas sensor 3F according to a fifth modification of the third embodiment is expressed as shown in FIG. 48A, and is taken along the line IIIF-IIIF in FIG.
  • FIG. 48A A schematic cross-sectional structure of the gas sensor 3F in which the MEMS beam structure is formed in a boat-type structure is expressed as shown in FIG.
  • the limiting current type gas sensor 3F includes a plurality of openings 471... Provided in the gas diffusion path MP, as shown in FIGS. 48 (a) and 48 (b). Any one of 472 (for example, the gas inlet 472) is closed by a lid member 49 such as a glass frit, a SiN film, or a SiO 2 film after the gas diffusion path MP is formed.
  • a lid member 49 such as a glass frit, a SiN film, or a SiO 2 film after the gas diffusion path MP is formed.
  • the gas diffusion path MP can be easily formed by using the two gas intake ports 471 and 472.
  • any of the gas intake ports 471 and 472 is blocked by the lid member 49, thereby suppressing an excessive increase in the amount of gas to be measured.
  • the limiting current type gas sensor according to the fifth modification of the third embodiment the sensor characteristics can be easily improved, and the gas diffusion path can be more easily formed and the gas introduction can be performed. As the amount increases, it is possible to solve the problem that the gas throttling performance decreases.
  • the limiting current type gas sensor 3F it is easy to insert a low-concentration doped polysilicon layer 300 having high thermal conductivity below the microheater MH, or to form the MEMS beam structure in an open structure. .
  • FIG. 49A A schematic plane pattern configuration of the limiting current type gas sensor 4A according to the fourth embodiment is expressed as shown in FIG. 49A, and the MEMS beam structure along the IVA-IVA line in FIG.
  • a schematic cross-sectional structure of the gas sensor 4A provided is represented as shown in FIG.
  • the limiting current type gas sensor 4A according to the fourth embodiment is such that a porous oxide film 71 is further disposed below the lower electrode 28D of the above limiting current type gas sensor 3A. Since the configuration of is basically the same, redundant description will be omitted as much as possible, and the configuration of the characteristic part will be described in more detail.
  • the limiting current type gas sensor 4A includes a gas introduction path arranged in the active region on the substrate 12 as the sensor portion SP.
  • a gas diffusion path MP As a gas diffusion path MP, a porous oxide film (porous film) 71, a lower electrode (Pt / Ti laminated film) 28D disposed on the porous oxide film 71, and the porous oxide film 71 and the lower electrode 28D are covered.
  • a solid electrolyte layer (YSZ film) 30 arranged in this manner, and an upper electrode (for example, Pt film) 28U arranged on the solid electrolyte layer 30 facing the lower electrode 28D.
  • the gas to be measured for example, O 2 gas
  • the gas to be measured is taken into the sensor portion SP from the gas diffusion path MP formed with a hollow structure as the microheater MH is heated.
  • the gas to be measured for example, O 2 gas
  • the porous oxide film 71 and the lower electrode 28D of the gas introduction port 41 they are diffused into the solid electrolyte layer 30.
  • the introduction of the measurement gas into the solid electrolyte layer 30 may involve a suction operation.
  • porous oxide film 71 may be formed by sputtering and etching in a process preceding the formation process of the lower electrode 28D when manufacturing the limit current gas sensor 3A described above.
  • the cavity portion C is substantially larger than the micro heater MH as in the case of the limiting current type gas sensor 3A described above.
  • the porous oxide film 71 has high thermal stability, it is possible to obtain a limiting current type gas sensor 4A having high gas throttling performance and excellent sensor characteristics.
  • the aspect ratio of the gas diffusion path MP can be easily increased by increasing the flow path length of the micro flow path 42 of the gas diffusion path MP or by reducing the cross-sectional area. Can be offset.
  • the limiting current type gas sensor according to the fourth embodiment, the sensor characteristics can be easily improved, and the sensor characteristics can be further stabilized.
  • FIG. 50A A schematic plane pattern configuration of the limiting current gas sensor 4B according to the first modification of the fourth embodiment is expressed as shown in FIG. 50A, and is along the line IVB-IVB in FIG. 50A.
  • FIG. 50A A schematic cross-sectional structure of the gas sensor 4B formed in the MEMS beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 4B is a MEMS beam structure having a cavity portion of an open type structure in which the substrate 12 is disposed so as to surround the sensor portion SP in plan view. It may be formed with C.
  • the cavity C of the open structure can be easily formed by, for example, deeply etching the substrate 12 from the back side after forming the cavity C of the boat structure.
  • the sensor characteristics can be easily improved, and the limit current gas sensor 4B capable of further stabilizing the sensor characteristics can be obtained. .
  • FIG. 51A A schematic plane pattern configuration of a limit current gas sensor 4C according to a second modification of the fourth embodiment is expressed as shown in FIG. 51A, and is along the IVC-IVC line in FIG.
  • FIG. 51A A schematic cross-sectional structure of the gas sensor 4C formed in the MEMS beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 4C according to the second modified example of the fourth embodiment is configured to increase the thermal conductivity in the membrane within the surface and make the temperature uniform.
  • the thermal conductivity is high below the microheater MH.
  • the limiting current type gas sensor 4C according to the second modification of the fourth embodiment is configured such that a lightly doped polysilicon layer (for example, 140 W / mK) 300 is inserted.
  • FIG. 52A A schematic plane pattern configuration of a limiting current gas sensor 4D according to a third modification of the fourth embodiment is expressed as shown in FIG. 52A, and is along the IVD-IVD line in FIG. 52A.
  • FIG. 52A A schematic cross-sectional structure of the gas sensor 4D formed in the MEMS beam structure is expressed as shown in FIG.
  • the low-concentration doped polycrystal having high thermal conductivity is provided below the microheater MH.
  • the limiting current gas sensor 4D according to the third modification of the fourth embodiment is configured to insert the silicon layer 300.
  • FIG. 53 (a) A schematic plane pattern configuration of a limiting current type gas sensor 4E according to a fourth modification of the fourth embodiment is expressed as shown in FIG. 53 (a) and is along the IVE-IVE line in FIG. 53 (a).
  • FIG. 53 (a) A schematic cross-sectional structure of the gas sensor 4E formed in the MEMS beam structure is expressed as shown in FIG.
  • a low-concentration doped polysilicon layer (for example, 140 W / mK) 300 having high thermal conductivity is inserted below the microheater MH.
  • a low-concentration doped polysilicon layer 300 having high thermal conductivity is inserted below the microheater MH.
  • FIG. 54A A schematic plane pattern configuration of a limiting current type gas sensor 4F according to a fifth modification of the fourth embodiment is expressed as shown in FIG. 54A, and is along the IVF-IVF line in FIG.
  • FIG. 54A A schematic cross-sectional structure of the gas sensor 4F formed in the MEMS beam structure is expressed as shown in FIG.
  • a low-concentration doped polysilicon layer (for example, 140 W / mK) 300 having high thermal conductivity is inserted below the microheater MH.
  • FIG. 55A A schematic plane pattern configuration of a limiting current type gas sensor 4G according to a sixth modification of the fourth embodiment is expressed as shown in FIG. 55A, and follows the IVG-IVG line in FIG. 55A.
  • FIG. 55A A schematic cross-sectional structure of the gas sensor 4G in which the MEMS beam structure is formed in a boat-type structure is expressed as shown in FIG.
  • the limiting current type gas sensor 4G according to the sixth modification of the fourth embodiment has, for example, the left end side of the sensor portion SP in plan view, as shown in FIGS. 55 (a) and 55 (b).
  • the gas diffusion path MP has openings (gas intake ports) 471 and 472.
  • the polysilicon film constituting the flow path forming layer 35 is efficiently wet etched by using the two openings 471 and 472. It is possible.
  • the sensor characteristics can be easily improved, and the gas diffusion path can be formed more easily. Become.
  • the limiting current type gas sensor 4G it is easy to insert a low-concentration doped polysilicon layer 300 having high thermal conductivity under the microheater MH, or to form the MEMS beam structure in an open structure. .
  • FIG. 56 (a) A schematic plane pattern configuration of the limiting current type gas sensor 4H according to the seventh modification of the fourth embodiment is expressed as shown in FIG. 56 (a) and is along the IVH-IVH line in FIG. 56 (a).
  • FIG. 56 (a) A schematic cross-sectional structure of the gas sensor 4H in which the MEMS beam structure is formed in a boat-type structure is expressed as shown in FIG.
  • the limiting current type gas sensor 4H according to the seventh modification of the fourth embodiment includes a plurality of openings 471... Provided in the gas diffusion path MP as shown in FIGS. 56 (a) and 56 (b). Either one of 472 (for example, the gas intake port 472) is closed by a lid member 49 such as a glass frit, a SiN film, or a SiO 2 film after the gas diffusion path MP is formed.
  • a lid member 49 such as a glass frit, a SiN film, or a SiO 2 film after the gas diffusion path MP is formed.
  • the gas diffusion path MP can be easily formed by using the two gas intake ports 471 and 472 in the step of forming the gas diffusion path MP.
  • one of the gas intake ports 471 and 472 is closed by the lid member 49, so that the introduction amount of the gas to be measured can be suppressed from being excessively increased.
  • the limiting current type gas sensor according to the seventh modification of the fourth embodiment the sensor characteristics can be easily improved, and the gas diffusion path can be formed more easily, and the gas introduction can be performed. As the amount increases, it is possible to solve the problem that the gas throttling performance decreases.
  • the limiting current type gas sensor 4H it is easy to insert a low-concentration doped polysilicon layer 300 having high thermal conductivity under the microheater MH, or to form the MEMS beam structure in an open structure. .
  • the limiting current type gas sensor includes the substrate 12, the heater MH disposed on the substrate 12 via the first insulating layer 181 and the second insulating layer 182 above the heater MH.
  • the gas intake part 303 arranged on the gas intake part 303, the lower electrode 28D arranged on the gas intake part 303, the solid electrolyte layer 30 arranged on the lower electrode 28D, and the lower electrode 28D on the solid electrolyte layer 30
  • the upper electrode 28U disposed on the surface opposite to the substrate 12 and a cavity portion C formed substantially larger than the heater MH on the substrate 12, and the gas intake portion 303 is a gas introduction path for taking in the gas to be measured.
  • a columnar film (columnar portion) that is disposed on the gas introduction path and has a gas throttle structure in a direction perpendicular to the surface.
  • the gas diffusion path MP1 has a gas throttle structure in the in-plane direction, and the columnar films 53 and 57 have a gas throttle structure in the perpendicular direction.
  • a schematic plane pattern configuration of the limiting current type gas sensor 5A1 according to the first example of the fifth embodiment is expressed as shown in FIG. 57 (a), and is along the line VA1-VA1 of FIG. 57 (a).
  • a schematic cross-sectional structure of the gas sensor 5A1 formed in the MEMS beam structure is expressed as shown in FIG.
  • the sensor portion SP of the limiting current type gas sensor 5A1 has a gas diffusion path (having a hollow structure (see FIG. 57A and FIG. 57B)).
  • Gas introduction path) MP1 columnar oxide film (columnar film) 53 disposed on the gas diffusion path MP1, porous oxide film 51 disposed to cover the columnar oxide film 53, and disposed on the porous oxide film 51
  • the lower electrode (Pt / Ti laminated film) 28D, the solid electrolyte layer 30 disposed so as to cover the porous oxide film 51 and the lower electrode 28D, and the solid electrolyte layer 30 opposed to the lower electrode 28D.
  • an upper electrode 28U an upper electrode 28U.
  • the porous oxide film 51 and the lower electrode 28D constitute a porous electrode, and the gas diffusion path MP1 and the columnar oxide film 53 form a gas intake.
  • the insertion unit 303 is configured.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure, but the limits shown in FIGS. 58 (a) and 58 (b).
  • the cavity portion C may have an open structure such as the current type gas sensor 5A2.
  • FIG. 59 (a) A schematic plane pattern configuration of the limiting current type gas sensor 5B1 according to the first modification of the first example of the fifth embodiment is expressed as shown in FIG. 59 (a), and VB1- A schematic cross-sectional structure of the gas sensor 5B1 formed in the MEMS beam structure along the line VB1 is expressed as shown in FIG.
  • the sensor portion SP of the limiting current gas sensor 5B1 has a hollow structure as shown in FIGS. 59 (a) and 59 (b).
  • the lower electrode 28DA constitutes a porous electrode
  • the gas diffusion path MP1 and the columnar oxide film 53 constitute a gas intake part. 303 is configured.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-shaped structure as in the limiting current gas sensor 5B1 illustrated in FIG. 59B, but is illustrated in FIGS. 60A and 60B. It may be a cavity portion C having an open type structure like the current type gas sensor 5B2.
  • FIG. 61 (a) A schematic plane pattern configuration of a limit current gas sensor 5C1 according to the second modification of the first example of the fifth embodiment is expressed as shown in FIG. 61 (a), and VC1- A schematic cross-sectional structure of the gas sensor 5C1 formed in the MEMS beam structure along the VC1 line is expressed as shown in FIG.
  • the sensor part SP of the limiting current type gas sensor 5C1 has a hollow structure as shown in FIGS. 61 (a) and 61 (b).
  • the lower electrode (Pt / Ti laminated film) 28D disposed on the porous oxide film 51, the solid electrolyte layer 30 disposed so as to cover the porous oxide film 51 and the lower electrode 28D, and the solid facing the lower electrode 28D And an upper electrode 28U disposed on the electrolyte layer 30.
  • the porous oxide film 51 and the lower electrode 28D constitute a porous electrode, and the gas diffusion path MP1 and the columnar Pt / Ti A gas intake part 303 is constituted by the film 57.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure, but the limits shown in FIGS. 62 (a) and 62 (b).
  • the cavity portion C may be an open type structure such as the current type gas sensor 5C2.
  • FIG. 63 (a) A schematic plane pattern configuration of the limiting current type gas sensor 5D1 according to the modification 3 of the first example of the fifth embodiment is expressed as shown in FIG. 63 (a), and VD1- of FIG. 63 (a).
  • FIG. 63 (a) A schematic cross-sectional structure of the gas sensor 5D1 formed in the MEMS beam structure along the line VD1 is expressed as shown in FIG.
  • the sensor portion SP of the limiting current type gas sensor 5D1 has a hollow structure as shown in FIGS. 63 (a) and 63 (b).
  • the lower electrode 28DA constitutes a porous electrode
  • the gas diffusion path MP1 and the columnar Pt / Ti film 57 constitute the gas collection.
  • the insertion unit 303 is configured.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-shaped structure as in the limiting current type gas sensor 5D1 illustrated in FIG. 63B, but is illustrated in FIGS. 64A and 64B.
  • the cavity portion C may have an open structure such as the current type gas sensor 5D2.
  • the porous oxide film 51 has a gas throttle structure in the in-plane direction
  • the columnar films 53 and 57 have a gas throttle structure in the perpendicular direction.
  • a schematic plane pattern configuration of the limiting current type gas sensor 5E1 according to the second example of the fifth embodiment is expressed as shown in FIG. 65 (a) and is along the VE1-VE1 line of FIG. 65 (a).
  • a schematic cross-sectional structure of the gas sensor 5E1 formed in the MEMS beam structure is expressed as shown in FIG.
  • the sensor portion SP of the limiting current type gas sensor 5E1 is a first gas introduction path as shown in FIGS. 65 (a) and 65 (b).
  • the second porous oxide film 51B and the lower electrode 28D constitute a porous electrode
  • the first porous oxide film 51A and the columnar oxide film A gas intake 303 is configured by the film 53.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure, but the limits shown in FIGS. 66 (a) and 66 (b).
  • the cavity portion C may have an open structure such as the current type gas sensor 5E2.
  • FIG. 67 (a) A schematic plane pattern configuration of the limiting current type gas sensor 5F1 according to the first modification of the second example of the fifth embodiment is expressed as shown in FIG. 67 (a), and VF1- of FIG. 67 (a).
  • FIG. 67 (a) A schematic cross-sectional structure of the gas sensor 5F1 formed in the MEMS beam structure along the VF1 line is expressed as shown in FIG.
  • the sensor part SP of the limiting current type gas sensor 5F1 includes a gas introduction path as shown in FIGS. 67 (a) and 67 (b).
  • a solid electrolyte layer 30 disposed to cover the electrode 28DA and an upper electrode 28U disposed on the solid electrolyte layer 30 facing the lower electrode 28DA.
  • the lower electrode 28DA forms a porous electrode, and the porous oxide film 51 and the columnar oxide film 53 form a gas intake part. 303 is configured.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure as in the limiting current type gas sensor 5F1 illustrated in FIG. 67B, but is illustrated in FIGS. 68A and 68B.
  • the cavity portion C may have an open structure such as the current type gas sensor 5F2.
  • FIG. 69 (a) A schematic plane pattern configuration of the limiting current type gas sensor 5G1 according to the second modification of the second example of the fifth embodiment is expressed as shown in FIG. 69 (a), and VG1- of FIG. 69 (a).
  • FIG. 69 (a) A schematic cross-sectional structure of the gas sensor 5G1 formed in the MEMS beam structure along the line VG1 is expressed as shown in FIG.
  • the sensor part SP of the limiting current type gas sensor 5G1 includes a gas introduction path as shown in FIGS.
  • positioned on the solid electrolyte layer 30 facing the lower electrode 28D are provided.
  • the second porous oxide film 51B and the lower electrode 28D constitute a porous electrode, and the first porous oxide film.
  • 51 A and the columnar Pt / Ti film 57 constitute a gas intake portion 303.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure, but the limits shown in FIGS. 70 (a) and 70 (b).
  • the cavity portion C may have an open structure such as the current type gas sensor 5G2.
  • FIG. 71 (a) A schematic planar pattern configuration of the limiting current type gas sensor 5H1 according to the third modification of the second example of the fifth embodiment is expressed as shown in FIG. 71 (a), and VH1- of FIG. 71 (a).
  • FIG. 71 (a) A schematic cross-sectional structure of the gas sensor 5H1 formed in the MEMS beam structure along the VH1 line is expressed as shown in FIG.
  • the sensor part SP of the limiting current type gas sensor 5H1 includes a gas introduction path as shown in FIGS. 71 (a) and 71 (b).
  • a porous electrode is constituted by the lower electrode 28DA, and the porous oxide film 51 and the columnar Pt / Ti film 57 are used for gas collection.
  • the insertion unit 303 is configured.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure, but the limits shown in FIGS. 72 (a) and 72 (b).
  • the cavity portion C may have an open structure such as the current type gas sensor 5H2.
  • the porous Pt film 61 has a gas throttle structure in the in-plane direction, and the columnar films 53 and 57 have a gas throttle structure in the perpendicular direction.
  • a schematic plane pattern configuration of the limiting current type gas sensor 5J1 according to the third example of the fifth embodiment is expressed as shown in FIG. 73A, and is taken along the line VJ1-VJ1 of FIG. 73A.
  • a schematic cross-sectional structure of the gas sensor 5J1 formed in the MEMS beam structure is expressed as shown in FIG.
  • the sensor portion SP of the limiting current type gas sensor 5J1 is a porous Pt film that serves as a gas introduction path as shown in FIGS. 73 (a) and 73 (b).
  • the porous oxide film 51 and the lower electrode 28D constitute a porous electrode, and the porous Pt film 61 and the columnar oxide film 53 form a gas trap.
  • the insertion unit 303 is configured.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure, but the limits shown in FIGS. 74 (a) and 74 (b).
  • the cavity portion C may have an open structure such as the current type gas sensor 5J2.
  • FIG. 75 (a) A schematic planar pattern configuration of the limiting current type gas sensor 5K1 according to the first modification of the third example of the fifth embodiment is expressed as shown in FIG. 75 (a), and is represented by VK1- in FIG. 75 (a).
  • FIG. 75 (a) A schematic cross-sectional structure of the gas sensor 5K1 formed in the MEMS beam structure along the VK1 line is expressed as shown in FIG.
  • the sensor portion SP of the limiting current gas sensor 5K1 includes a gas introduction path and A porous Pt film 61, a columnar oxide film (columnar film) 53 disposed on the porous Pt film 61, a lower electrode (porous Pt / Ti film) 28DA disposed so as to cover the columnar oxide film 53, and a lower part A solid electrolyte layer 30 disposed to cover the electrode 28DA and an upper electrode 28U disposed on the solid electrolyte layer 30 facing the lower electrode 28DA.
  • the lower electrode 28DA forms a porous electrode, and the porous Pt film 61 and the columnar oxide film 53 form a gas intake part. 303 is configured.
  • the porous Pt film 61 is adjusted such that the particle diameter ⁇ of Pt is larger than the particle diameter ⁇ of Pt of the lower electrode 28DA.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure as in the limiting current gas sensor 5K1 illustrated in FIG. 75B, but is illustrated in FIGS. 76A and 76B.
  • the cavity portion C may have an open structure such as the current type gas sensor 5K2.
  • FIG. 77 (a) A schematic planar pattern configuration of the limiting current gas sensor 5L1 according to the second modification of the third example of the fifth embodiment is expressed as shown in FIG. 77 (a), and VL1- of FIG. 77 (a).
  • FIG. 77 (b) A schematic cross-sectional structure of the gas sensor 5L1 formed in the MEMS beam structure along the VL1 line is expressed as shown in FIG. 77 (b).
  • the sensor portion SP of the limiting current type gas sensor 5L1 includes a gas introduction path as shown in FIGS. 77 (a) and 77 (b).
  • the porous oxide film 51 and the lower electrode 28D constitute a porous electrode, and the porous Pt film 61 and the columnar Pt / Ti.
  • a gas intake part 303 is constituted by the film 57.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure as in the limiting current type gas sensor 5L1 illustrated in FIG. 77B, but is illustrated in FIGS. 78A and 78B.
  • the cavity portion C may have an open structure such as the current type gas sensor 5L2.
  • FIG. 79 (a) A schematic planar pattern configuration of the limiting current type gas sensor 5M1 according to the third modification of the third example of the fifth embodiment is expressed as shown in FIG. 79 (a), and VM1- A schematic cross-sectional structure of the gas sensor 5M1 formed in the MEMS beam structure along the VM1 line is expressed as shown in FIG. 79 (b).
  • the sensor part SP of the limiting current type gas sensor 5M1 includes a gas introduction path as shown in FIGS. 79 (a) and 79 (b).
  • a porous electrode is constituted by the lower electrode 28DA, and the porous Pt film 61 and the columnar Pt / Ti film 57 are used to collect gas.
  • the insertion unit 303 is configured.
  • the porous Pt film 61 is adjusted such that the particle diameter ⁇ of Pt is larger than the particle diameter ⁇ of Pt of the lower electrode 28DA.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure as in the limiting current type gas sensor 5M1 illustrated in FIG. 79B, but is illustrated in FIGS. 80A and 80B.
  • the cavity portion C may have an open structure such as the current type gas sensor 5M2.
  • the temperature dependence of the porous film can be easily improved, and a limiting current type gas sensor capable of further stabilizing the sensor characteristics can be obtained.
  • porous Pt film 61 instead of the porous Pt film 61, a porous Pt / Ti film may be applied.
  • the limiting current type gas sensor includes the substrate 12, the heater MH disposed on the substrate 12 via the first insulating layer 181 and the second insulating layer 182 above the heater MH.
  • the gas intake unit 305 disposed on the lower electrode 28D, the lower electrode 28D disposed on the gas intake unit 305, the solid electrolyte layer 30 disposed on the lower electrode 28D, and the lower electrode 28D on the solid electrolyte layer 30
  • the upper electrode 28U disposed on the surface opposed to the substrate 12 and the cavity portion C formed substantially larger than the heater MH on the substrate 12, and the gas intake portion 305 is a gas introduction path for taking in the gas to be measured.
  • a porous film (columnar portion) disposed on the gas introduction path and having a gas diffusion structure in the in-plane direction.
  • the gas diffusion path MP1 has a gas throttle structure in the in-plane direction
  • the porous membranes 51 and 61 have a gas diffusion structure in the in-plane direction.
  • FIG. 81 (a) A schematic planar pattern configuration of the limiting current type gas sensor 6A1 according to the first example of the sixth embodiment is expressed as shown in FIG. 81 (a) and is along the line VIA1-VIA1 of FIG. 81 (a).
  • FIG. 81 (a) A schematic cross-sectional structure of the gas sensor 6A1 formed in the MEMS beam structure is expressed as shown in FIG.
  • the sensor portion SP of the limiting current type gas sensor 6A1 has a gas diffusion path (having a hollow structure (see FIG. 81A and FIG. 81B)).
  • Gas introduction path) MP1 porous oxide film (porous film) 51 disposed on gas diffusion path MP1, columnar oxide film 53 disposed so as to cover porous oxide film 51, and columnar oxide film 53
  • the lower electrode (Pt / Ti laminated film) 28D disposed, the solid electrolyte layer 30 disposed so as to cover the columnar oxide film 53 and the lower electrode 28D, and the solid electrolyte layer 30 opposed to the lower electrode 28D.
  • an upper electrode 28U an upper electrode 28U.
  • a columnar electrode is constituted by the columnar oxide film 53 and the lower electrode 28D, and the gas diffusion path MP1 and the porous oxide film 51 constitute a gas intake.
  • the insertion unit 305 is configured.
  • the columnar electrode has a gas throttle structure in a direction perpendicular to the plane.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-shaped structure as in the limiting current gas sensor 6A1 illustrated in FIG. 81B, but is illustrated in FIGS. 82A and 82B.
  • the cavity portion C may have an open structure such as the current type gas sensor 6A2.
  • FIG. 83 (a) A schematic plane pattern configuration of the limiting current type gas sensor 6B1 according to the first modification of the first example of the sixth embodiment is expressed as shown in FIG. 83 (a), and VIB1- of FIG. 83 (a).
  • FIG. 83 (a) A schematic cross-sectional structure of the gas sensor 6B1 formed in the MEMS beam structure along the VIB1 line is expressed as shown in FIG.
  • the sensor part SP of the limiting current type gas sensor 6B1 has a hollow structure as shown in FIGS. 83 (a) and 83 (b).
  • a columnar electrode is constituted by the lower electrode 28DB, and a gas intake part is constituted by the gas diffusion path MP1 and the porous oxide film 51. 305 is configured.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-shaped structure as in the limiting current gas sensor 6B1 illustrated in FIG. 83B, but is illustrated in FIGS. 84A and 84B.
  • the cavity portion C may have an open structure such as the current type gas sensor 6B2.
  • FIG. 85 (a) A schematic planar pattern configuration of the limiting current type gas sensor 6C1 according to the second modification of the first example of the sixth embodiment is expressed as shown in FIG. 85 (a), and VIC1- of FIG. 85 (a).
  • FIG. 85 (a) A schematic cross-sectional structure of the gas sensor 6C1 formed in the MEMS beam structure along the VIC1 line is expressed as shown in FIG. 85 (a).
  • the sensor part SP of the limiting current type gas sensor 6C1 has a hollow structure as shown in FIGS. 85 (a) and 85 (b).
  • a gas diffusion path (gas introduction path) MP1 a porous Pt film (porous film) 61 disposed on the gas diffusion path MP1, a columnar oxide film 53 disposed so as to cover the porous Pt film 61, and a columnar oxidation Lower electrode (Pt / Ti laminated film) 28D disposed on film 53, solid electrolyte layer 30 disposed to cover columnar oxide film 53 and lower electrode 28D, and solid electrolyte layer 30 opposed to lower electrode 28D And an upper electrode 28U disposed on the upper surface.
  • Pt / Ti laminated film Pt / Ti laminated film
  • a columnar electrode is constituted by the columnar oxide film 53 and the lower electrode 28D, and the gas diffusion path MP1 and the porous Pt film 61 are formed.
  • the gas intake part 305 is comprised by these.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-shaped structure as in the limiting current type gas sensor 6C1 illustrated in FIG. 85B, but is illustrated in FIGS. 86A and 86B.
  • the cavity portion C may have an open structure such as the current type gas sensor 6C2.
  • FIG. 87 (a) A schematic plane pattern configuration of the limiting current type gas sensor 6D1 according to the third modification of the first example of the sixth embodiment is expressed as shown in FIG. 87 (a), and VID1- of FIG. 87 (a).
  • FIG. 87 (b) A schematic cross-sectional structure of the gas sensor 6D1 formed in the MEMS beam structure along the VID1 line is expressed as shown in FIG. 87 (b).
  • the sensor part SP of the limiting current type gas sensor 6D1 has a hollow structure as shown in FIGS. 87 (a) and 87 (b).
  • a columnar electrode is constituted by the lower electrode 28DB, and the gas intake part is constituted by the gas diffusion path MP1 and the porous Pt film 61. 305 is configured.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-shaped structure as in the limiting current gas sensor 6D1 illustrated in FIG. 87B, but is illustrated in FIGS. 88A and 88B.
  • the cavity portion C may have an open structure such as the current type gas sensor 6D2.
  • porous membranes 51 and 61 have a gas throttle structure in the in-plane direction.
  • FIG. 89 (a) A schematic plane pattern configuration of the limiting current type gas sensor 6E1 according to the second example of the sixth embodiment is expressed as shown in FIG. 89 (a), and is along the line VIE1-VIE1 of FIG. 89 (a).
  • FIG. 89 (a) A schematic cross-sectional structure of the gas sensor 6E1 formed in the MEMS beam structure is expressed as shown in FIG.
  • the sensor portion SP of the limiting current type gas sensor 6E1 is the first gas introduction path as shown in FIGS. 89 (a) and 89 (b).
  • a lower electrode (Pt / Ti laminated film) 28D disposed on the columnar oxide film 53
  • a solid electrolyte layer 30 disposed to cover the columnar oxide film 53 and the lower electrode 28D, and the lower electrode 28D.
  • an upper electrode 28U disposed on the solid electrolyte layer 30.
  • the columnar electrode is constituted by the columnar oxide film 53 and the lower electrode 28D, and the first porous oxide film 51A and the second porous oxidation are formed.
  • a gas intake 305 is constituted by the film 51B.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-shaped structure as in the limiting current type gas sensor 6E1 illustrated in FIG. 89B, but is illustrated in FIGS. 90A and 90B.
  • the cavity portion C may have an open structure such as the current type gas sensor 6E2.
  • FIG. 91 (a) A schematic planar pattern configuration of the limiting current type gas sensor 6F1 according to the first modification of the second example of the sixth embodiment is expressed as shown in FIG. 91 (a), and VIF1- of FIG. 91 (a).
  • FIG. 91 (b) A schematic cross-sectional structure of the gas sensor 6F1 formed in the MEMS beam structure along the VIF1 line is expressed as shown in FIG. 91 (b).
  • the sensor portion SP of the limiting current type gas sensor 6F1 includes a gas introduction path and The first porous oxide film 51A, the second porous oxide film (porous film) 51B disposed on the first porous oxide film 51A, and the second porous oxide film 51B are disposed.
  • a lower electrode (columnar Pt / Ti film) 28DB, a solid electrolyte layer 30 arranged to cover the lower electrode 28DB, and an upper electrode 28U arranged on the solid electrolyte layer 30 facing the lower electrode 28DB are provided.
  • a columnar electrode is constituted by the lower electrode 28DB, and the first porous oxide film 51A and the second porous oxide film 51B.
  • the gas intake part 305 is comprised by these.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure as in the limiting current type gas sensor 6F1 illustrated in FIG. 91B, but is illustrated in FIGS. 92A and 92B.
  • the cavity portion C may have an open structure such as the current type gas sensor 6F2.
  • FIG. 93 (a) A schematic plane pattern configuration of the limiting current type gas sensor 6G1 according to the second modification of the second example of the sixth exemplary embodiment is expressed as shown in FIG. 93 (a), and VIG1- of FIG. 93 (a).
  • FIG. 93 (a) A schematic cross-sectional structure of the gas sensor 6G1 formed in the MEMS beam structure along the VIG1 line is expressed as shown in FIG.
  • the sensor part SP of the limiting current type gas sensor 6G1 includes a gas introduction path as shown in FIGS. 93 (a) and 93 (b).
  • the lower electrode (Pt / Ti laminated film) 28D disposed, the solid electrolyte layer 30 disposed so as to cover the columnar oxide film 53 and the lower electrode 28D, and the solid electrolyte layer 30 opposed to the lower electrode 28D.
  • an upper electrode 28U an upper electrode 28U.
  • the columnar electrode is constituted by the columnar oxide film 53 and the lower electrode 28D, and the porous oxide film 51 and the porous Pt film 61 are formed.
  • the gas intake part 305 is comprised by these.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-shaped structure as in the limiting current type gas sensor 6G1 illustrated in FIG. 93B, but is illustrated in FIGS. 94A and 94B.
  • the cavity portion C may have an open structure such as the current type gas sensor 6G2.
  • the sensor part SP of the limiting current type gas sensor 6H1 is configured such that the gas introduction path and the sensor part SP are as shown in FIG. 95 (a) and FIG.
  • the solid electrolyte layer 30 is disposed so as to cover the lower electrode 28DB, and the upper electrode 28U is disposed on the solid electrolyte layer 30 facing the lower electrode 28DB.
  • a columnar electrode is constituted by the lower electrode 28DB, and a gas intake part is constituted by the porous oxide film 51 and the porous Pt film 61. 305 is configured.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure as in the limiting current type gas sensor 6H1 illustrated in FIG. 95B, but is illustrated in FIGS. 96A and 96B.
  • the cavity portion C may have an open structure such as the current type gas sensor 6H2.
  • porous membranes 51 and 61 have a gas diffusion structure in the in-plane direction.
  • FIG. 97 (a) A schematic planar pattern configuration of the limiting current type gas sensor 6J1 according to the third example of the sixth embodiment is expressed as shown in FIG. 97 (a) and is along the line VIJ1-VIJ1 of FIG. 97 (a).
  • FIG. 97 (b) A schematic cross-sectional structure of the gas sensor 6J1 formed in the MEMS beam structure is expressed as shown in FIG. 97 (b).
  • the sensor portion SP of the limiting current type gas sensor 6J1 is a porous Pt film serving as a gas introduction path as shown in FIGS. 97 (a) and 97 (b).
  • 61 a porous oxide film (porous film) 51 disposed on the porous Pt film 61, a columnar oxide film 53 disposed so as to cover the porous oxide film 51, and a lower portion disposed on the columnar oxide film 53
  • the columnar electrode is constituted by the columnar oxide film 53 and the lower electrode 28D, and the porous Pt film 61 and the porous oxide film 51 are used for gas extraction.
  • the insertion unit 305 is configured.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure, but the limits shown in FIG. 98 (a) and FIG.
  • the cavity portion C may have an open structure like the current type gas sensor 6J2.
  • FIG. 99 (a) A schematic plane pattern configuration of the limiting current type gas sensor 6K1 according to the first modification of the third example of the sixth embodiment is expressed as shown in FIG. 99 (a), and VIK1- A schematic cross-sectional structure of the gas sensor 6K1 formed in the MEMS beam structure along the VIK1 line is expressed as shown in FIG. 99 (b).
  • the sensor part SP of the limiting current type gas sensor 6K1 includes a gas introduction path as shown in FIGS. 99 (a) and 99 (b).
  • the solid electrolyte layer 30 is disposed so as to cover the lower electrode 28DB, and the upper electrode 28U is disposed on the solid electrolyte layer 30 facing the lower electrode 28DB.
  • a columnar electrode is constituted by the lower electrode 28DB, and the gas intake part is constituted by the porous Pt film 61 and the porous oxide film 51. 305 is configured.
  • the cavity C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure as in the limiting current type gas sensor 6K1 illustrated in FIG. 99B, but is illustrated in FIGS. 100A and 100B.
  • the cavity portion C may have an open structure such as the current type gas sensor 6K2.
  • FIG. 101 (Modification 2 of the third example of the sixth embodiment)
  • FIG. 101 (a) A schematic plane pattern configuration of the limiting current type gas sensor 6L1 according to the second modification of the third example of the sixth exemplary embodiment is expressed as shown in FIG. 101 (a), and VIL1- of FIG. 101 (a).
  • FIG. 101 (a) A schematic cross-sectional structure of the gas sensor 6L1 formed in the MEMS beam structure along the VIL1 line is expressed as shown in FIG.
  • the sensor portion SP of the limiting current type gas sensor 6L1 includes a gas introduction path as shown in FIGS. 101 (a) and 101 (b).
  • the first porous Pt film 61A, the second porous Pt film (porous film) 61B disposed on the first porous Pt film 61A, and the second porous Pt film 61B are disposed.
  • the columnar oxide film 53 and the lower electrode 28D constitute a columnar electrode
  • the first porous Pt film 61A and the first The gas intake unit 305 is configured by the two porous Pt films 61B.
  • the cavity portion C of the substrate 12 having the MEMS beam structure is not limited to the boat-type structure as in the limiting current type gas sensor 6L1 illustrated in FIG. 101B, but is illustrated in FIGS. 102A and 102B.
  • the cavity portion C may have an open structure such as the current type gas sensor 6L2.
  • FIG. 103 A schematic planar pattern configuration of the limiting current type gas sensor 6M1 according to the third modification of the third example of the sixth exemplary embodiment is expressed as shown in FIG. 103 (a), and VIM1- of FIG. 103 (a).
  • FIG. 103 (a) A schematic cross-sectional structure of the gas sensor 6M1 formed in the MEMS beam structure along the line VIM1 is expressed as shown in FIG. 103 (a).
  • the sensor portion SP of the limiting current type gas sensor 6M1 is configured such that the gas introduction path and the sensor part SP are as shown in FIGS. 103 (a) and 103 (b).
  • the first porous Pt film 61A, the second porous Pt film (porous film) 61B disposed on the first porous Pt film 61A, and the second porous Pt film 61B are disposed.
  • a lower electrode (columnar Pt / Ti film) 28DB, a solid electrolyte layer 30 arranged to cover the lower electrode 28DB, and an upper electrode 28U arranged on the solid electrolyte layer 30 facing the lower electrode 28DB are provided.
  • a columnar electrode is constituted by the lower electrode 28DB, and the first porous Pt film 61A and the second porous Pt film 61B.
  • the gas intake part 305 is comprised by these.
  • the cavity portion C of the MEMS beam structure substrate 12 is not limited to the boat-shaped structure as in the limiting current type gas sensor 6M1 shown in FIG. 103 (b), but the limit shown in FIGS. 104 (a) and 104 (b).
  • the cavity portion C may have an open structure such as the current type gas sensor 6M2.
  • the temperature dependence of the porous film can be easily improved, and a limiting current type gas sensor capable of further stabilizing the sensor characteristics can be obtained.
  • porous Pt / Ti film may be applied instead of the porous Pt films 61, 61A, 61B.
  • FIG. 106 A flowchart showing the operation of detecting the gas concentration by the limiting current type gas sensor is expressed as shown in FIG. Further, in the limiting current type gas sensor, the relationship between the YSZ temperature and the time in the gas concentration detection operation is schematically represented as shown in FIG. 106, and a schematic sectional structure for explaining the operation principle is as shown in FIG. It is expressed in
  • the solid electrolyte layer 106 is ripened to several hundred degrees C., for example, about 500 degrees C. by the microheater MH, and a voltage V is applied between the upper electrode (cathode) 105U and the porous electrode (anode) 105D.
  • a voltage V is applied between the upper electrode (cathode) 105U and the porous electrode (anode) 105D.
  • oxygen ions (O 2 ⁇ ) are injected into the solid electrolyte layer 106 by the electrochemical reaction of O 2 + 4e ⁇ ⁇ 2O 2 ⁇ in the upper electrode 105U.
  • oxygen gas (O 2 gas) is released by the reaction of 2O 2 ⁇ O 2 + 4e ⁇ .
  • oxygen ions (O 2 ⁇ ) propagate based on hopping conduction.
  • an energy diagram for explaining the hopping conduction of oxygen ions (O 2 ⁇ ) is schematically represented as shown in FIG.
  • the electric field Ex is applied to the solid electrolyte layer 106
  • the bottom of the conductor is inclined by ⁇ eEx due to the effect. Accordingly, the height of the conduction barrier of oxygen ions (O 2 ⁇ ) is lowered, so that hopping conduction of oxygen ions (O 2 ⁇ ) is performed together with thermal excitation.
  • the limiting current in the current-voltage characteristic is schematically represented as shown in FIG. That is, in FIG. 109, the current appearing in period T 2 represents the limit current I O for oxygen gas, and the current appearing in period T 3 represents the limit current I W for water vapor.
  • the values of the limit currents I O and I W and the oxygen concentration and water vapor concentration values are associated in advance and registered in the detection circuit 107. Keep it. In this way, by measuring the value of the limit current I O ⁇ I W , the corresponding oxygen concentration / water vapor concentration can be detected.
  • T on the heater ON period, T off is equivalent to heater off period.
  • Heating power supplied to the heater on time T on is, for example, about 5 mW.
  • the senor is heated from room temperature to a measurement temperature (for example, 500 ° C.) using a micro heater (FIG. 105: Steps S1 ⁇ S2: NO ⁇ S1 ⁇ ).
  • a measurement temperature for example, 500 ° C.
  • a voltage is applied between the upper electrode 105U and the porous electrode 105D (FIG. 105: step S4).
  • step S5 Next, the value of the limit current is measured, and the gas concentration corresponding to the limit current is detected (FIG. 105: step S5).
  • the micro heater is turned off to cool the sensor.
  • heating, standby, measurement, and cooling may be repeated in a cycle of about once per minute.
  • oxygen ions O 2 ⁇ diffuse in the solid electrolyte layer 106 due to the electrochemical reaction of O 2 + 4e ⁇ ⁇ 2O 2 ⁇ .
  • the flow amount of the oxygen gas O 2 is larger than the diffusion amount of the oxygen ions O 2 ⁇ .
  • oxygen gas O 2 is released by the reaction of 2O 2 ⁇ O 2 + 4e ⁇ .
  • oxygen ions O 2 ⁇ are injected into the solid electrolyte layer 106 by an electrochemical reaction of O 2 + 4e ⁇ ⁇ 2O 2 ⁇ .
  • hydrogen is released by the electrochemical reaction of H 2 O + 2e ⁇ ⁇ H 2 + O 2 ⁇ . That is, water vapor (H 2 O) is electrolyzed, and oxygen ions O 2 ⁇ move in the solid electrolyte layer 106 by hopping conduction.
  • the oxygen gas O 2 is released due to the reaction of 2O 2 ⁇ O 2 + 4e ⁇ due to the electrolysis of the adsorbed oxygen gas O ad .
  • the release of oxygen gas O 2 occurs due to the reaction of 2O 2 ⁇ ⁇ O 2 + 4e ⁇ .
  • oxygen ions O 2 ⁇ are injected into the solid electrolyte layer 106 by an electrochemical reaction of O 2 + 4e ⁇ ⁇ 2O 2 ⁇ .
  • hydrogen is released by an electrochemical reaction of H 2 O + 2e ⁇ ⁇ H 2 + O 2 ⁇ . That is, water vapor (H 2 O) is electrolyzed, and oxygen ions O 2 ⁇ move through the solid electrolyte layer 106 by hopping conduction.
  • the oxygen gas O 2 is released due to the reaction of 2O 2 ⁇ O 2 + 4e ⁇ due to the electrolysis of the adsorbed oxygen gas O ad .
  • the release of oxygen gas O 2 occurs due to the reaction of 2O 2 ⁇ ⁇ O 2 + 4e ⁇ .
  • the oxygen vacancy concentration is also in equilibrium with the atmospheric oxygen partial pressure based on the following formula O O x ⁇ 1 / 2 ⁇ O 2 (g) + V O .. + 2e ′.
  • This equation shows that the electronic conductivity depends on the partial pressure of oxygen in equilibrium with the solid, and because the entropy of the generated system is higher at high temperatures, the reaction is biased to the right at high temperatures and also depends on temperature. .
  • FIG. 111 A schematic bird's-eye view configuration showing the lid 131 of the package that houses the limiting current type gas sensor according to each embodiment is expressed as shown in FIG.
  • the package lid 131 is formed with a large number of through holes 132 that allow gas to pass but not allow foreign matter to pass.
  • a metal mesh, a small hole metal, a porous ceramic, or the like can be applied for the lid 131 of the package.
  • FIG. 112 A schematic bird's-eye view configuration showing the main body 141 of the package that houses the limiting current type gas sensor according to each embodiment is expressed as shown in FIG.
  • a limit current type gas sensor chip 142 having a plurality of terminals is accommodated in a main body 141 of the package, and is electrically connected by a plurality of bonding wires 143.
  • a lid 131 is placed on the top of the package main body 141 and mounted on a printed circuit board by soldering.
  • the limit current gas sensor (sensor node) according to each embodiment includes sensors 151, a wireless module 152, a microcomputer 153, an energy harvester power supply 154, and a storage element 155.
  • the configuration of the sensors 151 is as described in each embodiment.
  • the wireless module 152 is a module including an RF circuit that transmits and receives wireless signals.
  • the microcomputer 153 has a management function of the energy harvester power supply 154, and inputs power from the energy harvester power supply 154 to the sensors 151. At this time, the microcomputer 153 may input power based on a heater power profile that saves power consumed by the sensors 151.
  • the second power that is relatively small power may be input for the second period T2.
  • data may be read during the second period T2, and after the second period T2 has elapsed, the power supply may be stopped for the third period T3.
  • the energy harvester power supply 154 collects energy such as sunlight, illumination light, vibration generated by the machine, and heat to obtain electric power.
  • the power storage element 155 is a lithium ion power storage element capable of storing power.
  • the power from the energy harvester power supply 154 is supplied to the microcomputer 153.
  • the microcomputer 153 boosts the voltage from the energy harvester power source 154, as indicated by (2) in FIG.
  • the wireless module 152 wirelessly transmits data such as the sensor resistance value and the Pt resistance value.
  • a sensor package 96 equipped with the limiting current type gas sensor includes a temperature sensor thermistor 90, a humidity / oxygen sensor YSZ sensor 92, a thermistor 90.
  • An AD / DA converter 94 that receives analog information SA 2 and SA 1 from the YSZ sensor unit 92 and supplies control signals S 2 and S 1 to the thermistor unit 90 and YSZ sensor unit 92, and digital input / output from the outside Signal DI / DO is provided.
  • thermistor section 90 for example, an NTC thermistor, a PTC thermistor, a ceramic PTC, a polymer PTC, a CTR thermistor or the like can be applied.
  • the limiting current type gas sensor according to each embodiment can be applied to the YSZ sensor unit 92.
  • the YSZ sensor unit 92 can also measure absolute humidity (Absolute Humidity) and relative humidity (RH: Relative Humidity). However, the temperature is used as a reference when detecting the relative humidity (RH). The detected temperature information is required.
  • the sensor network is a network in which a large number of sensors are connected to each other. New initiatives using sensor networks have already begun in various fields such as factories, medical / healthcare, transportation, construction, agriculture, and environmental management.
  • the limiting current type gas sensor according to each embodiment as, for example, a humidity sensor. Since such a humidity sensor uses zirconia, it has excellent durability. Therefore, it is possible to provide a highly reliable sensor network.
  • FIG. 116 (a) A schematic planar pattern configuration of the sensor portion of the limiting current gas sensor 1A according to the seventh embodiment is expressed as shown in FIG. 116 (a), and is a MEMS along the line IA-IA in FIG. 116 (a).
  • FIG. 116 (a) A schematic cross-sectional structure of a sensor portion formed in a beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 1A corresponds to the MEMS beam structure substrate 12 and the center sensor portion, as shown in FIGS. 116 (a) and 116 (b).
  • the porous electrode (Ti / Pt electrode) 5D disposed on the substrate 12, the Pt + YSZ mixed particle film (particle mixed layer) 11 formed on the porous electrode 5D, and the Pt + YSZ mixed particle film 11 are surrounded.
  • Pt is platinum as a porous material
  • Ti is titanium as an electrode material
  • YSZ is yttrium stabilized zirconia (Yttria-Stabilized Zirconia) as a solid electrolyte material. is there.
  • this limiting current type gas sensor 1A includes a porous electrode 5D, a Pt + YSZ mixed grain film 11, a solid electrolyte layer 4, and a dense electrode at least in the sensor portion.
  • a porous membrane (porous layer) 13 is provided so as to cover 5U.
  • the porous film 13 is formed using Al 2 O 3 —SiO 2 or the like so as to have a thickness of about 5 ⁇ m, for example.
  • the limiting current type gas sensor 1A has an insulating layer 3 as shown in FIGS. 116 (a) and 116 (b), and openings 3b and 3b patterned on the insulating layer 3.
  • the extended end side of the porous electrode 5D is connected to one detection terminal 2b, and the extended end (second dense electrode portion) side of the dense electrode 5U is connected to the other detection terminal 2b.
  • the insulating layer 3 is formed of, for example, a SiON film (silicon vagina film) having a thickness of 1 ⁇ m.
  • the detection terminals 2b and 2b are polysilicon layers having a thickness of about 400 nm, and are formed at a higher concentration than the microheater 2 described later by ion implantation.
  • the dense electrode 5U has a surface facing the Pt + YSZ mixed-grain film 11 of the solid electrolyte layer 4 in the sensor portion as a first dense electrode portion, and partially includes a part of the first dense electrode portion, An extended portion extending from a part of the first dense electrode portion is used as a second dense electrode portion, the first dense electrode portion is made of Pt (first electrode material), and the second dense electrode portion is made of Ti.
  • a (second electrode material) / Pt laminated film may be used.
  • the porous electrode 5D is formed of a Ti / Pt laminated film, for example, with a thickness of about 0.1 ⁇ m or more. This is because Pt aggregates and insulates if it is thin. Note that the porous electrode 5D can be formed using porous Pt having a pore diameter of about several ⁇ m.
  • the solid electrolyte layer 4 is made of YSZ having a thickness of about 0.3 ⁇ m or more. This is because if the thickness is small, the upper and lower electrodes 5D and 5U are electrically connected.
  • the solid electrolyte layer 4 is disposed so as to cover the outer peripheral portion of the Pt + YSZ mixed grain film 11 and the end of the porous electrode 5D on the side where the Pt + YSZ mixed grain film 11 is formed. Continuity between the upper and lower electrodes 5D and 5U is prevented.
  • the Pt + YSZ mixed-grain film 11 is disposed at the interface between the solid electrolyte layer 4 and the porous electrode 5D, and has a thickness of about 10 nm to 1000 nm, for example.
  • the Pt + YSZ mixed film 11 is formed by mixing Pt particles and YSZ particles while maintaining the shape of the particles, for example, oxygen at the time of gas concentration detection in the sensor portion between the solid electrolyte layer 4 and the porous electrode 5D.
  • the response speed of (O) can be improved (details will be described later).
  • the substrate 12 having the MEMS beam structure is disposed so as to surround the sensor portion in a plan view, and is formed of, for example, a SiON film having a thickness of about 2 ⁇ m.
  • the dense electrode 5U is disposed in contact with the surface of the solid electrolyte layer 4 facing the porous electrode 5D and the Pt + YSZ mixed-grain film 11, and is formed in a metal particle sintered layer and a metal particle sintered layer (not shown).
  • a fine gas introduction path (not shown).
  • the electrodes 5D and 5U themselves are formed in a nanostructure. That is, a sintered metal particle layer (dense Pt) in which Pt mixed with carbon nanotubes (CNT) is sintered and CNTs are finally burned to form a fine gas introduction path may be applied as the dense electrode 5U. Carbon nanoparticles may be applied instead of CNTs.
  • the thickness of the dense electrode 5U formed of dense Pt is, for example, about 0.1 ⁇ m or more. If it is too thin, Pt aggregates and insulates.
  • the fine gas introduction path in the dense electrode 5U can be formed by, for example, a heat treatment process of nanowires, nanotubes, nanoparticles, etc. having nanometer scale contained in the metal particle sintered layer or an etching process combined with a heat treatment process. It is. Nanowires, nanotubes, and nanoparticles can be formed from, for example, carbon (C), zinc oxide (ZnO), and the like.
  • the metal particle sintered layer in the dense electrode 5U and the fine gas introduction path formed in the metal particle sintered layer will not be described in detail here, but the metal particle sintered layer includes nanowires. May be.
  • the nanowire may comprise CNT or ZnO.
  • the metal particle sintered layer includes carbon nanotubes or carbon nanoparticles, and the fine gas introduction path is formed by burning the carbon nano nanotubes or carbon nanoparticles by burning the metal particle sintered layer in the atmosphere. It may be formed.
  • the metal particle sintered layer may include ZnO, and the fine gas introduction path may be formed by etching ZnO by wet etching after burning the metal particle sintered layer in the atmosphere.
  • the metal particles of the metal particle sintered layer may include any one of Pt, Ag, Pd, Au, or Ru.
  • the metal particle sintered layer may include nanowires that are confined in the metal particle sintered layer and are not burned by combustion in the atmosphere.
  • the nanowire or nanoparticle has a diameter of about 0.1 ⁇ m or less.
  • the length of the nanowire is, for example, about 10 ⁇ m or less.
  • the merit of using the nanowire is that the gas permeation amount can be controlled by the shape (diameter and length) of the nanowire, and the gas permeation amount can be controlled by the ratio of the nanowire.
  • the limiting current type gas sensor 1A can control the gas permeation amount by the shape of the fine gas introduction path of the dense electrode 5U.
  • the limiting current gas sensor 1A can control the gas permeation amount by the content ratio of the fine gas introduction path of the dense electrode 5U.
  • the limiting current gas sensor 1A has an insulating layer (for example, 1 ⁇ m thick) disposed on the substrate 12 having the MEMS beam structure.
  • (SiON film) 1a is further provided, and at least between the insulating layer 1a and the insulating layer 3 of the sensor portion, a heating microheater 2 is embedded in the same layer as the detection terminals 2b and 2b.
  • the microheater 2 is a polysilicon layer (polysilicon heater) having a thickness of about 400 nm, and has a resistance value of about 300 ⁇ by ion implantation.
  • the microheater 2 heats the solid electrolyte layer 4 by applying a predetermined voltage between heater electrode portions (Ti / Pt laminated films) 9 and 9 connected to the electrode layers 2a and 2a.
  • the micro heater 2 can also be formed by a Pt heater formed by printing.
  • the limiting current type gas sensor 1A has a MEMS element structure with a double-supported beam structure as a basic structure, thereby reducing the heat capacity of the sensor portion and improving the sensor sensitivity.
  • the microheater 2 is limited to the case where the microheater 2 is disposed between the substrate 12 and the porous electrode 5D, which are the upper part of the substrate 12, via the insulating layers 1a and 3. Instead, it may be disposed on the lower surface of the insulating layer 1 a facing the surface on which the porous electrode 5 ⁇ / b> D is formed, or on the lower portion of the substrate 12.
  • the microheater 2 may be embedded in the substrate 12.
  • a structure in which a silicon oxide film / silicon nitride film 103 including the microheater 2 formed of polysilicon is formed on the surface of the substrate 12 (see, for example, FIG. 148).
  • a detection voltage supplied to the dense electrode 5U and the porous electrode 5D is detected.
  • a detection circuit 107 for detecting a predetermined gas concentration in the gas to be measured by a limiting current type is connected.
  • the detection circuit 107 can detect the oxygen concentration based on the limit current.
  • the detection circuit 107 can detect the water vapor concentration based on the limit current.
  • the detection terminals 2b and 2b and the heater electrode portions 9 and 9 are arranged so that their extending directions are substantially orthogonal to each other.
  • the Pt + YSZ mixed-grain film 11 is disposed between the porous electrode 5D and the solid electrolyte layer 4, so that oxygen at the time of gas concentration detection in the sensor portion is detected. It is possible to improve the response speed of oxygen in the gas (O 2 ).
  • the basic configuration of the sensor portion of the limiting current type gas sensor 1A is formed using a silicon substrate 12 and a stacked film of Pt and Ti on the silicon substrate 12, as shown in FIG.
  • a grain film (particle mixed layer) 11 and a Pt electrode 5U disposed on the surface of the YSZ thin film 4 facing at least the Pt + YSZ mixed grain film 11 are provided.
  • FIG. 118 A basic schematic cross-sectional structure of the Pt + YSZ mixed-grain film 11 and a schematic cross-sectional structure showing a part of the Pt + YSZ mixed-grain film 11 (a circled portion in the drawing) in an enlarged manner are shown in FIG. 118 (a). Represented as shown.
  • the Pt + YSZ mixed-grain film 11 is mainly present in a layer (Pt region) 11a in which Pt mainly maintains the shape of the particles, and YSZ mainly maintains the shape of the particles.
  • the layer (YSZ region) 11b to be mixed is in a nested state, and the Pt particles and the YSZ particles are adjacent to each other at the boundary portion where the layer 11a and the layer 11b are in contact with each other.
  • the Pt particles of the layer 11a and the YSZ particles of the layer 11b are more mixed together, and the YSZ thin film 4 and Ti / A Pt electrode 5D is laminated.
  • the layer 11b has a structure in which a tip portion protruding toward the layer 11a is folded back, a structure in which a part of the protruding layer 11b is branched in a branch shape, or the like. Also good.
  • the Pt + YSZ mixed grain film 11 is formed by laminating the layer 11a and the layer 11b between the YSZ thin film 4 and the Ti / Pt electrode 5D, and the layer 11a and the layer 11b are mixed. More accurate sensing is possible by improving the area.
  • the state of nesting can be formed not only by the layer 11a and the layer 11b being laminated but also by annealing the laminated YSZ thin film 4 and the Ti / Pt electrode 5D.
  • FIG. 119 (a) schematically shows a case where the Pt particles and the YSZ particles do not exist adjacent to each other for comparison.
  • FIG. 119 (a) when Pt particles and YSZ particles are adjacent to each other, the movement distance LC of oxygen (O) moving between the Pt particles and YSZ particles is shown in FIG. 119 (b). As shown in FIG. 4, when the Pt particles and the YSZ particles are not adjacent, the moving distance LN of oxygen (O) moving between the Pt particles and the YSZ particles becomes shorter.
  • the Pt particles in contact with the YSZ particles can be increased, thereby shortening the movement time of oxygen (O). More accurate sensing can be realized.
  • the current value converges to “1” when the Pt + YSZ mixed-grain film 11 is provided (W11) as compared to the case where the Pt + YSZ mixed-grain film 11 is not provided (WO11). It is possible to shorten the time until the operation.
  • the limiting current type gas sensor 1A by providing the Pt + YSZ mixed-grain film 11, oxygen at the time of gas concentration detection in the sensor portion between the solid electrolyte layer 4 and the porous electrode 5D is detected.
  • the response speed can be improved, and the response speed as the limiting current type gas sensor 1A can be improved.
  • the manufacturing method of the limiting current type gas sensor 1A according to the seventh embodiment includes a step of forming a Ti / Pt electrode 5D using a laminated film of Pt and Ti on a silicon substrate 12 corresponding to the sensor portion, A step of forming a Pt + YSZ mixed particle film (particle mixed layer) 11 in which Pt particles and YSZ particles are mixed at least on the sensor portion on the Pt electrode 5D, and Ti / Pt so as to cover at least the Pt + YSZ mixed particle film 11 A step of forming the YSZ thin film 4 on the electrode 5D and a step of forming the Pt electrode 5U on at least the surface facing the Pt + YSZ mixed grain film 11 including the upper surface portion of the YSZ thin film 4 are included.
  • FIGS. 116 (a) and 116 (b) the manufacturing method of the limiting current type gas sensor 1A according to the seventh embodiment shown in FIGS. 116 (a) and 116 (b) is expressed as shown in FIGS.
  • a silicon substrate 12 having a thickness of about 10 ⁇ m is prepared, and about 1 ⁇ m is formed on the upper surface of the silicon substrate 12 by plasma CVD (P-CVD).
  • a thick SiON film 1a is formed.
  • a polysilicon layer having a thickness of about 400 nm is formed on the SiON film 1a, and the polysilicon layer is patterned by etching or the like.
  • the detection terminals 2b and 2b, the microheater 2, and the electrode layers 2a and 2a connected to the microheater 2 are formed in directions orthogonal to each other.
  • the microheater 2 is set so that the resistance value between the electrode layers 2a and 2a is 300 ⁇ , and the detection terminals 2b and 2b and the electrode layers 2a and 2a are higher in concentration than the microheater 2. Formed.
  • a SiON film 3 having a thickness of about 1 ⁇ m is formed on the entire surface by P-CVD. Then, the SiON film 3 is patterned to form openings 3a and 3b, and a part of the electrode layers 2a and 2a connected to the detection terminals 2b and 2b and the microheater 2 is selectively exposed.
  • a Ti / Pt electrode 5D and heater electrode portions 9, 9 having a thickness of 500 nm are formed by sputtering or the like, and Ti extending from the sensor portion is formed.
  • the extending end of the / Pt electrode 5D is on one detection terminal 2b exposed at the opening 3b of the SiON film 3, and the heater electrode portions 9 and 9 are on the electrode layers 2a and 2a exposed at the opening 3a of the SiON film 3. , Connect them respectively.
  • the Pt + YSZ mixed-grain film 11 can also be formed by performing a printing and sintering process using a mixed paste of YSZ particles and Pt particles.
  • the YSZ thin film 4 is formed to a thickness of 0.5 ⁇ m by the lift-off process, and the Ti / Pt electrode 5D of the sensor portion is formed by the YSZ thin film 4. And the periphery of the Pt + YSZ mixed-grain film 11.
  • the dense electrode 5U may be formed by forming the Pt film 5Pt after forming the Ti / Pt laminated film 5Ti.
  • the silicon substrate 12 corresponding to the sensor portion is selectively etched to form a cavity C (Cavity: Forming a cavity).
  • the cavity C is preferably about 300 ⁇ m ⁇ 300 ⁇ m although it depends on the size of the limiting current gas sensor 1A according to the present embodiment.
  • a porous film for example, an Al 2 O 3 —SiO 2 film 13 having a thickness of about 5 ⁇ m is formed by printing so as to cover the sensor portion, so that FIGS.
  • the limiting current type gas sensor 1A according to the seventh embodiment having the configuration shown in (b) is completed.
  • the response speed at the time of gas concentration detection can be improved by arranging the Pt + YSZ mixed-grain film 11.
  • FIG. 129 A schematic planar pattern configuration of the limiting current gas sensor 1A according to the eighth embodiment is represented as shown in FIG. 129, and an enlarged schematic planar pattern configuration of the main part is represented as shown in FIG.
  • FIG. 129 A schematic cross-sectional structure of a sensor portion formed in a MEMS (Micro Electro Mechanical Systems) beam structure along the line IIA-IIA in FIG. 130 is expressed as shown in FIG.
  • MEMS Micro Electro Mechanical Systems
  • the limiting current type gas sensor 1A includes a substrate 12 having a MEMS beam structure, a porous electrode 5D disposed on the substrate 12, and a porous material.
  • a metal particle sintered layer (not shown) and a fine gas introduction path (not shown) formed in the metal particle sintered layer are disposed substantially vertically with respect to the substrate 12. And a dense electrode 5U.
  • the limiting current type gas sensor 1A has an insulating film 8 disposed on a porous electrode 5D via a Pt + YSZ mixed grain film 11, and an opening patterned in the insulating film 8 is provided.
  • the solid electrolyte layer 4 is disposed on the Pt + YSZ mixed grain film 11 in the part 7 and on the insulating film 8 surrounding the opening 7.
  • the limiting current type gas sensor 1A may include an insulating layer 3 disposed on the substrate 12, and the porous electrode 5D may be disposed on the insulating layer 3.
  • the porous electrode 5D is formed of a porous material made of porous Pt having a pore diameter of about several ⁇ m. For example, the thickness is about 1 ⁇ m or more and prevents Pt from aggregating and insulating.
  • the porous electrode 5D can also be formed of a Ti / Pt laminated film.
  • the solid electrolyte layer 4 is formed of YSZ (Yttria-Stabilized Zirconia) having a thickness of about 4 ⁇ m or more, which is a solid electrolyte material. This is because if the thickness is small, the upper and lower electrodes 5D and 5U are electrically connected.
  • YSZ Yttria-Stabilized Zirconia
  • the substrate 12 having a MEMS beam structure is formed of a silicon substrate having a thickness of about 10 ⁇ m, for example.
  • the electrodes 5D and 5U themselves are formed in a nanostructure. That is, Pt mixed with carbon nanotubes (CNT) is sintered, and finally the metal particle sintered layer (dense Pt) formed by burning CNTs to form a fine gas introduction path is applied as the dense electrode 5U. Carbon nanoparticles may be applied instead of CNTs.
  • CNT carbon nanotubes
  • the thickness of the dense electrode 5U formed of dense Pt is, for example, about 1 ⁇ m or more. If it is too thin, Pt aggregates and insulates.
  • a limiting current type gas sensor 1A according to the eighth embodiment since the uptake of oxygen gas can be controlled by the dense electrode 5U, a limiting current type gas sensor having excellent limiting current characteristics and improved detection sensitivity can be obtained. Can be provided.
  • the metal particle sintered layer that becomes the dense electrode 5U is provided with CNT or carbon nanoparticles, and the fine gas introduction path is such that the CNT or carbon nanoparticles are burned by the combustion of the metal particle sintered layer in the atmosphere. May be formed.
  • the metal particle sintered layer includes zinc oxide (ZnO), and the fine gas introduction path is formed by etching the ZnO by wet etching after burning the metal particle sintered layer in the atmosphere. Also good.
  • ZnO zinc oxide
  • the limiting current type gas sensor 1A according to the eighth embodiment can control the gas permeation amount by the shape of the fine gas introduction path.
  • the limiting current type gas sensor 1A according to the eighth embodiment can control the gas permeation amount by the content ratio of the fine gas introduction path.
  • the metal particles of the metal particle sintered layer may include any one of Pt, Ag, Pd, Au, or Ru.
  • the limiting current type gas sensor 1A applies a voltage between the dense electrode 5U and the porous electrode 5D to thereby obtain a predetermined gas concentration in the gas to be measured.
  • the detection circuit 107 can detect the oxygen concentration based on the limit current.
  • the detection circuit 107 can detect the water vapor concentration based on the limit current.
  • the limiting current type gas sensor 1A by providing the Pt + YSZ mixed grain film 11, it is possible to improve the response speed of oxygen at the time of gas concentration detection, and as the limiting current type gas sensor 1A Can improve the response speed.
  • the limiting current type gas sensor 1A includes a first stress relaxation low thermal expansion film 6 (5U) disposed on the dense electrode 5U, and a Pt + YSZ mixed grain.
  • the second low stress expansion film 6 (5D) for stress relaxation disposed on the porous electrode 5D on which the film 11 is formed, and the third low stress expansion film 6 (4) for stress relaxation disposed on the solid electrolyte layer 4 And may be provided.
  • the limiting current type gas sensor 1A has a first low stress thermal expansion film 6 (5U) and a third low thermal expansion film for stress relaxation, as seen in a plan view. 6 (4), the first warp suppressing porous insulating film 10 (5U) disposed on the dense electrode 5U, and the second stress relaxation low thermal expansion film 6 (5D) in plan view. And the second stress-reducing low thermal expansion film 6 (4), the second warp suppressing porous insulating film 10 (5D) disposed on the porous electrode 5D via the Pt + YSZ mixed grain film 11 And may be provided.
  • the limiting current type gas sensor 1A includes a MEMS element structure of a doubly supported beam structure as a basic structure. Although the detailed structure will be described later, a sensor portion is disposed in the center portion, and a porous electrode 5D and a dense electrode 5U connected to the sensor portion are disposed in the beam portion of the both-end supported beam structure. A detection circuit 107 is connected between the dense electrodes 5U.
  • a microheater 2 for heating is embedded in the central sensor part, and the heat capacity of the central sensor part is reduced by using a MEMS element structure of a double-supported beam structure as a basic structure. We are trying to improve.
  • the substrate 12 includes a micro heater 2 as shown in FIG.
  • the microheater 2 may be disposed on the top of the substrate 12 or on the bottom of the substrate 12. Further, the microheater 2 may be embedded in the substrate 12 as shown in FIG.
  • the micro heater 2 can be formed by, for example, a Pt heater formed by printing or a polysilicon heater. Also, a silicon oxide / silicon nitride film 103 including the microheater 2 made of polysilicon may be formed on the surface of the substrate 12 (see, for example, FIG. 148).
  • the porous electrode 5D and the dense electrode 5U can be formed of a porous Pt electrode.
  • the porous Pt electrode can be formed by printing, vapor deposition, or sputtering.
  • the thicknesses of the porous electrode 5D and the dense electrode 5U are, for example, about 0.1 ⁇ m to 10 ⁇ m.
  • the insulating film 8 can be formed of any of Al 2 O 3 , Al 2 O 3 —SiO 2 , YSZ—SiO 2 , or YSZ—Al 2 O 3 .
  • the insulating film 8 can be formed by a printing process or a sputtering process.
  • the thickness of the insulating film 8 is, for example, about 1.0 ⁇ m to 10 ⁇ m.
  • the solid electrolyte layer 4 can be formed of a stabilized zirconia (YSZ) film containing at least one of YSZ, YSZ—SiO 2 , or YSZ—Al 2 O 3 .
  • the solid electrolyte layer 4 can be formed by a printing process or a sputtering process.
  • the thickness of the solid electrolyte layer 4 is, for example, about 0.1 ⁇ m to 10 ⁇ m.
  • the low thermal expansion film 6 for stress relaxation can adjust the film density depending on the amount of gas to be detected.
  • the low thermal expansion film 6 for stress relaxation can be formed of a dense film, a porous film, or a composite film of a dense film and a porous film.
  • the stress relaxation low thermal expansion film 6 may be formed of a material containing at least one of SiO 2 , Al 2 O 3 , YSZ, or mullite. Moreover, the low thermal expansion film 6 for stress relaxation can be formed by a printing process or a sputtering process. The thickness of the low thermal expansion film 6 for stress relaxation is, for example, about 1.0 ⁇ m to 5.0 ⁇ m.
  • the warp suppressing porous insulating film 10 may be formed of a material including at least one of SiO 2 , Al 2 O 3 , YSZ, or mullite.
  • the warp suppressing porous insulating film 10 can be formed by a printing process or a sputtering process.
  • the thickness of the warp suppressing porous insulating film 10 is, for example, about 1.0 ⁇ m to 5.0 ⁇ m.
  • the substrate 12 may have a MEMS beam structure.
  • the substrate 12 can be formed of a silicon substrate having a thickness of 10 ⁇ m or less, preferably 2 ⁇ m or less. If MEMS is applied, the thickness of the substrate 12 can be reduced to 2 ⁇ m or less, so that the heat capacity is reduced and the power consumption in the microheater 2 can be reduced.
  • the limiting current type gas sensor 1A according to the eighth embodiment is formed as a doubly supported beam structure on a cavity C (cavity) formed in the substrate 12, as shown in FIGS. Has been.
  • the beam structure is a beam structure formed by MEMS and having a thickness of 10 ⁇ m or less, preferably 2 ⁇ m or less.
  • the insulating layer 3 can be formed of a porous film containing any of Al 2 O 3 , Al 2 O 3 —SiO 2 , YSZ—SiO 2 , or YSZ—Al 2 O 3 .
  • the insulating layer 3 functions as a gas intake film and can be formed by a printing process or a sputtering process.
  • the thickness of the insulating layer 3 is, for example, about 0 to 10 ⁇ m.
  • the insulating layer 3 is not necessarily provided. In that case, a porous electrode 5D that can be formed of a porous Pt electrode can be used as the gas-intake film.
  • Such a limiting current type gas sensor 1A may be manufactured by a method other than MEMS.
  • the thickness of the silicon substrate 12 is, for example, about 600 ⁇ m.
  • the manufacturing method of the limiting current type gas sensor 1A according to the eighth embodiment includes a step of forming a porous electrode (porous Pt) 5D on the substrate 12, and a porous electrode 5D.
  • the dense electrode 5U includes a metal particle sintered layer and a fine gas introduction path formed in the metal particle sintered layer.
  • the Pt + YSZ mixed grain film 11 may be selectively formed only on at least a part of the porous electrode 5D corresponding to the opening 7, for example.
  • the manufacturing method of the limiting current type gas sensor 1A forms the first stress relaxation low thermal expansion film 6 (5U) on the dense electrode 5U, and mixes Pt + YSZ.
  • a second stress relaxation low thermal expansion film 6 (5D) is formed on the porous electrode 5D on which the grain film 11 is formed, and a third stress relaxation low thermal expansion film 6 (4) is formed on the solid electrolyte layer 4.
  • the method for manufacturing the limiting current gas sensor 1 ⁇ / b> A includes the first stress relaxation low thermal expansion film 6 (5 U) and the third stress relaxation low heat, as seen in a plan view.
  • the second warp suppressing porous insulating film 10 (5D) is formed on the porous electrode 5D on which the Pt + YSZ mixed-grain film 11 is formed. ).
  • the substrate 12 is etched in the direction of the arrow in the figure, and both ends are supported on the cavity C formed in the substrate 12. Forming a beam structure.
  • the method for manufacturing the limiting current gas sensor 1A according to the eighth embodiment may include a step of forming the microheater 2 on the top of the substrate 12 or on the bottom of the substrate 12.
  • the method for manufacturing the limiting current gas sensor 1A according to the eighth embodiment may include a step of forming the microheater 2 embedded in the substrate 12.
  • the manufacturing method of the limiting current type gas sensor 1A according to the eighth embodiment may include the step of forming the insulating layer 3 on the substrate 12, and the porous electrode 5D may be formed on the insulating layer 3. .
  • the microheater 2 the insulating layer 3, the porous electrode 5D, the dense electrode 5U, the insulating film 8, the solid electrolyte layer 4, and the low heat for stress relaxation.
  • the expansion film 6 (6 (4) ⁇ 6 (5U) ⁇ 6 (5D)
  • the warp-suppressing porous insulating film 10 (10 (5U) ⁇ 10 (5D)
  • the Pt + YSZ mixed-grain film 11 are printed in the printing process. Can be formed.
  • FIG. 132 to 139 a method for manufacturing the limiting current type gas sensor 1A according to the eighth embodiment will be described with reference to FIGS. 132 to 139.
  • FIG. 132 to 139 a method for manufacturing the limiting current type gas sensor 1A according to the eighth embodiment will be described with reference to FIGS. 132 to 139.
  • the insulating layer 3 is formed on the substrate 12 in which the microheater 2 is embedded.
  • the insulating layer 3 is a porous film, it becomes a gas passage. The formation of the insulating layer 3 may be omitted.
  • a porous electrode 5D is formed on the insulating layer 3 and the substrate 12. Since the porous electrode 5D is formed of, for example, a porous Pt electrode, gas may pass through the porous Pt electrode.
  • the Pt + YSZ mixed grain film 11 is formed on the upper surface thereof.
  • the Pt + YSZ mixed grain film 11 is formed by, for example, forming a laminated film of a 2 nm thick YSZ film and a 2 nm thick Pt film by a sputtering method, and then performing an annealing process at 1000 ° C., or using a mixed paste of YSZ particles and Pt particles. It can be formed by printing and sintering.
  • the Pt + YSZ mixed grain film 11 is formed on a part of the upper surface of the porous electrode 5D, by forming the insulating film 8, a stabilized zirconia (solid electrolyte layer 4) / porous Pt electrode (porous)
  • the contact area between the electrodes 5D) is stabilized, contact between the end face of the stabilized zirconia (solid electrolyte layer 4) and the porous Pt electrode (porous electrode 5D) is eliminated, and the porous Pt electrode (porous electrode 5D) is eliminated.
  • the Pt electrode (dense electrode 5U) can be removed.
  • the solid electrolyte layer 4 is formed on the Pt + YSZ mixed-grain film 11 in the opening 7 and on the insulating film 8 surrounding the opening 7. .
  • the solid electrolyte layer 4 is formed of YSZ here, for example.
  • the dense electrode is opposed to the porous electrode 5D and substantially vertically with respect to the substrate 12.
  • 5U is formed.
  • the dense electrode 5U is also formed to extend on the insulating film 8, the insulating layer 3, and the substrate 12, as shown in FIG. 136 (a).
  • the dense electrode 5U is formed by, for example, a porous Pt electrode.
  • the first stress relaxation low thermal expansion film 6 (5U) is formed on the dense electrode 5U, and the Pt + YSZ mixed-grain film 11 is formed.
  • the second stress relaxation low thermal expansion film 6 (5D) is formed on the porous electrode 5D, and the third stress relaxation low thermal expansion film 6 (4) is formed on the solid electrolyte layer 4.
  • the stress relaxation low thermal expansion film 6 can adjust the film density according to the amount of gas to be detected.
  • the low thermal expansion film 6 for stress relaxation can be formed of any one of a dense film, a porous film, or a composite film of a dense film and a porous film.
  • the stress relaxation low thermal expansion film 6 is formed of a material containing at least one of SiO 2 , Al 2 O 3 , YSZ, or mullite.
  • the low thermal expansion film 6 for stress relaxation can be formed by a printing process or a sputtering process.
  • the low thermal expansion film 6 for stress relaxation is an insulating film having a low thermal expansion coefficient. By forming the low thermal expansion film 6 for stress relaxation, stress during heating can be relaxed.
  • the first warp suppressing porous insulating film 10 is formed on the dense electrode 5U, and the second stress relaxation low thermal expansion film 6 (5D) and the third stress relaxation low thermal expansion film 6 ( 4), the second warp suppressing porous insulating film 10 (5D) is formed on the porous electrode 5D.
  • the warp suppressing porous insulating film 10 is formed of a material containing at least one of SiO 2 , Al 2 O 3 , YSZ, or mullite.
  • the warp suppressing porous insulating film 10 can be formed by a printing process or a sputtering process. By forming the warp-suppressing porous insulating film 10, it is possible to reduce the warp of the beam structure during heating and improve the durability.
  • the limiting current type gas sensor 1A according to the eighth embodiment also provides a response speed at the time of gas concentration detection by arranging the Pt + YSZ mixed-grain film 11 as in the seventh embodiment. Can improve.
  • FIG. 129 A schematic plane pattern configuration of a limiting current type gas sensor 1A according to the ninth embodiment is expressed as shown in FIG.
  • FIG. 129 An example in which the porous electrode 5D and the porous electrode 5U are arranged only on one of the two arms on one side of the four arms of the double-supported beam structure. showed that.
  • the porous electrodes 5D 1 and 5D 2 are formed on both arms of the two arms on one side of the four arms of the doubly supported beam structure.
  • the dense electrodes 5U 1 and 5U 2 are arranged.
  • the porous electrodes 5D 1 and 5D 2 are electrically connected to each other.
  • the dense electrodes 5U 1 and 5U 2 are also electrically connected to each other.
  • a limiting current type gas sensor 1A includes a substrate 12, porous electrodes 5D 1 and 5D 2 disposed on the substrate 12, and a porous electrode at least in the sensor portion.
  • Pt + YSZ mixed grain film (particle mixed layer) 11 formed on 5D
  • insulating film 8 (not shown) disposed on porous electrode 5D on which Pt + YSZ mixed grain film 11 is formed, and patterned on insulating film 8
  • the solid electrolyte layer 4 disposed on the Pt + YSZ mixed grain film 11 in the opening 7 (not shown) and the insulating film 8 surrounding the opening 7, and the solid electrolyte layer facing the porous electrodes 5D 1 and 5D 2 4 is provided with dense electrodes 5U 1 and 5U 2 that are disposed substantially vertically with respect to the substrate 12 and have a metal particle sintered layer and a fine gas introduction path formed in the metal particle sintered layer.
  • the limiting current type gas sensor 1A applies a voltage between the dense electrodes 5U 1 and 5U 2 and the porous electrodes 5D 1 and 5D 2 as shown in FIG. And a detection circuit 107 for detecting a predetermined gas concentration in the gas to be measured by a limiting current type.
  • the detection circuit 107 can detect the oxygen concentration based on the limit current.
  • the detection circuit 107 can detect the water vapor concentration based on the limit current.
  • the limiting current type gas sensor 1A according to the ninth embodiment, by providing the Pt + YSZ mixed-grain film 11, it is possible to improve the response speed of oxygen at the time of gas concentration detection, and the limiting current type gas sensor The response speed as 1A can be improved.
  • the limiting current type gas sensor 1A includes a first thermal relaxation low thermal expansion film 6 (5U 1 ), which is disposed on the dense electrodes 5U 1 , 5U 2. 6 (5U 2 ), the second low stress expansion film 6 (5D 1 ) ⁇ 6 (5D 2 ) for stress relaxation disposed on the porous electrodes 5D 1 and 5D 2 , and the solid electrolyte layer 4 You may provide the 3rd low thermal expansion film
  • the limiting current type gas sensor 1A has a first stress relaxation low thermal expansion film 6 (5U 1 ), 6 (5U 2 ) and a third one in plan view.
  • the first warp suppressing porous insulating films 10 (5U 1 ) and 10 (5U 2 ) disposed on the dense electrodes 5U 1 and 5U 2 across the low thermal expansion film 6 (4) for stress relaxation
  • the porous electrode 5D 1 ... Spans between the second stress relaxation low thermal expansion film 6 (5D 1 ), 6 (5D 2 ) and the third stress relaxation low thermal expansion film 6 (4).
  • the insulating layer 3 disposed on the substrate 12 may be provided, and the porous electrodes 5D 1 and 5D 2 may be disposed on the insulating layer 3.
  • the manufacturing method of the limiting current type gas sensor 1A according to the ninth embodiment is a process of forming porous electrodes 5D, 5D 1 and 5D 2 on the substrate 12 as shown in FIGS. 141 to 144 (FIG. 141).
  • a step of forming the Pt + YSZ mixed-grain film 11 on the porous electrode 5D a step of forming the insulating film 8 on the porous electrode 5D on which the Pt + YSZ mixed-particle film 11 is formed, and patterning the insulating film 8
  • a step of forming the opening 7 FIG.
  • the manufacturing method of the limiting current type gas sensor 1A according to the ninth embodiment includes a first stress relaxation low thermal expansion film 6 (5U 1 ), on the dense electrodes 5U 1 and 5U 2.
  • the manufacturing method of the limiting current type gas sensor 1 ⁇ / b > A has the first stress relaxation low thermal expansion films 6 (5 U 1 ) and 6 (5 U 2 ) in plan view. And the third stress relaxation low thermal expansion film 6 (4), the first warp suppressing porous insulating film 10 (10 (5 U 1 ), 10 (5 U 2) on the dense electrodes 5 U 1 , 5 U 2.
  • the substrate 12 is etched, and a beam structure having both ends supported on the cavity C formed in the substrate 12 is obtained. Forming a step.
  • the manufacturing method of the limiting current type gas sensor 1A according to the ninth embodiment has a step of forming the insulating layer 3 on the substrate 12, as shown in FIG. 140, and the porous electrode is formed on the insulating layer 3. 5D, 5D 1 and 5D 2 may be formed.
  • the porous electrodes 5D 1 , 5D 2, and the dense electrode 5U are provided on both arms of the two arms on one side of the four arms of the doubly supported beam structure. Since only the structure in which 1 ⁇ 5U 2 is arranged is different from that of the eighth embodiment (for example, see FIG. 129), most of the detailed manufacturing steps of each part are the same as those of the eighth embodiment.
  • the limiting current type gas sensor 1A according to the ninth embodiment also has a Pt + YSZ mixed-grain film 11 disposed in the same manner as in the seventh and eighth embodiments. Response speed can be improved.
  • FIG. 147 A schematic cross-sectional structure showing one process (beam structure forming process) of the manufacturing method of the limiting current type gas sensor 1A according to the seventh to ninth embodiments is represented as shown in FIG.
  • One process (another beam structure forming process) of the manufacturing method of the limiting current type gas sensor 1A according to the seventh to ninth embodiments is expressed as shown in FIG. 147 (b).
  • FIG. 147 (b) it is possible to form a hull structure in which the cavity C is formed inside the substrate 12. In either case, for example, anisotropic etching of a silicon substrate can be applied.
  • the device heating unit 200 represents the vertical sensor structure of the limiting current gas sensor 1A.
  • FIG. 148 (a) the layout diagram (top view) of the beam structure of the limiting current gas sensor 1A according to the eighth and ninth embodiments is represented as shown in FIG. 148 (a), and is shown in FIG.
  • FIG. 148 (b) A schematic cross-sectional structure along the line -IIIA is expressed as shown in FIG. 148 (b).
  • a silicon substrate having a (100) plane is used as the substrate 12, and the bottom of the device heating unit 200 is formed with a (100) plane on the bottom and a (111) plane on the side by anisotropic etching.
  • a cavity C is formed.
  • a laminated film 103 of silicon oxide film / silicon nitride film including a microheater made of polysilicon is formed on the surface of this substrate 12.
  • the area of the device heating unit 200 is, for example, about 0.1 mm 2 .
  • the laminated film 103 including the microheater is formed on the bottom of the device heating unit 200 having the vertical sensor structure, and the substrate 12 is removed. Yes. That is, as in this structural example, in the limiting current type gas sensor 1A according to the eighth and ninth embodiments, the thinned substrate 12 is removed, and only the laminated film 103 including the microheater is present. It may be formed.
  • the microheater 2 can be formed by the following process flow.
  • a 3 ⁇ m-thick PSG (Phosphorus Silicon Glass) film is formed on the silicon substrate 12, and after forming a SiN film thereon, the SiN film is patterned (the SiN film is removed from the heavily doped portion).
  • PSG Phosphorus Silicon Glass
  • a polysilicon layer is formed, and P (phosphorus) is diffused into the polysilicon layer, for example, by a heat treatment at about 1000 ° C. to form a highly doped polysilicon layer.
  • the portion with the SiN film becomes a lightly doped polysilicon layer.
  • a vertical sensor structure is formed, and a beam structure is formed by PSG etching with BHF (5: 1).
  • the beam-structured micro heater 2 can be easily formed on the cavity C.
  • the microheater 2 disposed in the laminated film 103 in FIGS. 148 (a) and 148 (b) has the following process flow. You may make it form by.
  • a laminated film 103 which is a multilayer insulating film of SiO 2 / SiN / SiO 2 is formed on a Si (100) substrate 12, and a Pt heater (microheater 2) is formed thereon.
  • the device heating unit 200 is formed on the microheater 2.
  • the cavity C is formed by anisotropically etching the silicon substrate 12 using the TMAH solution.
  • the micro-heater 2 having a beam structure can be easily formed on the cavity C by such a process.
  • the operation of detecting the gas concentration in the limiting current type gas sensors according to the seventh to ninth embodiments is performed as described above, as described in the limiting current type gas sensors according to the first to sixth embodiments. Since this is substantially the same as the case of, detailed description is omitted.
  • the description of the electrochemical reaction is substantially the same as the case of the limiting current type gas sensor according to the first to sixth embodiments as described above, and thus detailed description thereof is omitted.
  • the package is substantially the same as that of the limiting current type gas sensor according to the first to sixth embodiments, and thus detailed description thereof is omitted.
  • the configuration example of the sensor node using the energy harvester power supply is substantially the same as the case of the limiting current type gas sensor according to the first to sixth embodiments described above, and detailed description thereof is omitted.
  • the schematic block configuration of the sensor package is substantially the same as that of the limiting current type gas sensor according to the first to sixth embodiments described above. The detailed description is omitted.
  • the schematic block configuration of the sensor network system to which the limit current type gas sensor according to the seventh to ninth embodiments is applied is the same as the case of the limit current type gas sensor according to the first to sixth embodiments described above. Since it is substantially the same, detailed description here is abbreviate
  • FIG. 149 (a) A schematic planar pattern configuration of the limiting current type gas sensor 1A according to the tenth embodiment is expressed as shown in FIG. 149 (a), and is arranged along the IA-IA line in FIG. 149 (a).
  • Mechanical Systems A schematic cross-sectional structure of the sensor 1A formed in the beam structure is expressed as shown in FIG.
  • the limiting current type gas sensor 1A corresponds to the MEMS beam structure substrate 12 and the center sensor portion, as shown in FIGS. 149 (a) and 149 (b).
  • the porous electrode (porous Pt electrode) 5D disposed on the substrate 12, the solid electrolyte layer (YSZ film) 4 disposed so as to cover the porous electrode 5D, and the solid electrolyte facing the porous electrode 5D
  • a dense electrode (porous Pt electrode) 5 ⁇ / b> U disposed substantially vertically with respect to the substrate 12 is provided.
  • the limiting current type gas sensor 1A has an insulating layer 3 on almost the entire surface, and a gas to be measured (via a gas diffusion path 15 formed on the upper layer portion of the insulating layer 3 with a predetermined aspect ratio (for example, O 2 gas) is introduced toward the sensor portion.
  • a gas to be measured via a gas diffusion path 15 formed on the upper layer portion of the insulating layer 3 with a predetermined aspect ratio ( For example, O 2 gas) is introduced toward the sensor portion.
  • the limiting current type gas sensor 1A includes a substrate 12, a porous electrode 5D arranged in the region of the sensor portion on the substrate 12 via the insulating layer 3, and a porous electrode 5D.
  • the gas diffusion path 15 includes a gas intake port 15b that takes in the gas to be measured, a gas introduction port 15c that introduces the gas to be measured, and a gas flow path (micro flow path) that connects the gas introduction port 15c and the gas intake port 15b. 15a, and the flow rate of the gas to be measured can be controlled according to the aspect ratio (ratio between the channel length of the microchannel and the channel cross-sectional area).
  • the limiting current type gas sensor 1A can control the flow rate of the gas to be measured according to the aspect ratio of the gas flow path 15a, and can improve the sensor characteristics by increasing the aspect ratio.
  • the sensor characteristics can be further stabilized by increasing the accuracy of formation of the gas diffusion path 15.
  • the gas inlet 15b of the gas diffusion path 15 is provided in an open state corresponding to the region of the non-sensor portion on the upper layer side of the insulating layer 3, and the gas inlet 15c is formed on the upper layer of the insulating layer 3.
  • the gas channel 15a is provided in an open state above, and is embedded in the upper part of the insulating layer 3 in a substantially horizontal direction.
  • the limiting current type gas sensor 1A includes heater electrode portions (Pt / Ti laminated films) 9a and 9a embedded in the openings 3a and 3a patterned in the insulating layer 3.
  • a predetermined voltage for heating the solid electrolyte layer 4 is applied to the microheater 2 connected to the electrode layers 2a and 2a.
  • the limiting current type gas sensor 1A is insulated from one or the other detection terminals 9b and 9b in which, for example, a Pt / Ti laminated film is embedded in the openings 3b and 3b in the insulating layer 3.
  • the openings 3c and 3c in the layer 3 further include one and the other connection terminals 9c and 9c in which, for example, a Pt / Ti laminated film is embedded.
  • the one and the other detection terminals 9b and 9b and the one and the other connection terminals 9c and 9c are connected via the electrode layers 2b and 2b in the same layer as the electrode layers 2a and 2a, respectively.
  • the detection circuit 107 for detecting a predetermined gas concentration in the gas to be measured by a limiting current type is connected to the one / other detection terminals 9b and 9b. Further, one connecting terminal 9c connected to one detection terminal 9b has an extending end of the porous electrode 5D, and the other connecting terminal 9c connected to the other detecting terminal 9b has an extending end of the dense electrode 5U. , Each connected.
  • Pt is platinum as a porous material
  • Ti is titanium as an electrode material
  • YSZ is yttrium stabilized zirconia (Yttria-Stabilized Zirconia) as a solid electrolyte material. is there.
  • the insulating layer 3 is formed of, for example, a SiON film (silicon vagina film) having a thickness of 1.0 ⁇ m or more.
  • the electrode layers 2a and 2a and the electrode layers 2b and 2b are polysilicon layers having a thickness of about 0.3 ⁇ m, and are formed at a higher concentration than the microheater 2 by ion implantation.
  • the heater electrode portions 9a and 9a, the detection terminals 9b and 9b, and the connection terminals 9c and 9c are formed of, for example, a laminated film of a 20 nm thick Ti film and a 100 nm thick Pt film.
  • the porous electrode 5D is formed of a porous Pt film, for example, with a thickness of about 100 nm. It should be noted that a Ti / Pt laminated film having a pore diameter of about several ⁇ m can be used for forming the porous electrode 5D.
  • the solid electrolyte layer 4 is formed of a YSZ film having a thickness of about 1 ⁇ m. This is because if the thickness is small, the upper and lower electrodes 5D and 5U are electrically connected. For example, the solid electrolyte layer 4 is disposed so as to cover the periphery of the porous electrode 5D, and conduction between the upper and lower electrodes 5D and 5U is prevented.
  • the substrate 12 having a MEMS beam structure has an open structure arranged so as to surround the sensor portion in a plan view, and is formed of, for example, a silicon substrate having a thickness of about 10 ⁇ m.
  • the porous electrode 5D is disposed on the surface of the gas diffusion path 15 facing the gas introduction port 15c, and a fine gas introduction path (not shown) formed in the metal particle sintered layer and the metal particle sintered layer described later. Z).
  • the electrodes 5D and 5U themselves are formed in a nanostructure. That is, a sintered metal particle layer (dense Pt) in which Pt mixed with carbon nanotubes (CNT) is sintered and CNTs are finally burned to form a fine gas introduction path may be applied as the porous electrode 5D. .
  • Carbon nanoparticles may be applied instead of CNTs.
  • the fine gas introduction path in the porous electrode 5D is formed by, for example, a heat treatment process of nanowires, nanotubes, nanoparticles, etc. having nanometer scale contained in the metal particle sintered layer or an etching process combined with a heat treatment process.
  • Nanowires, nanotubes, and nanoparticles can be formed from, for example, carbon (C), zinc oxide (ZnO), and the like.
  • the metal particle sintered layer in the porous electrode 5D and the fine gas introduction path formed in the metal particle sintered layer will not be described in detail here, but the metal particle sintered layer includes nanowires. May be.
  • the nanowire may comprise CNT or ZnO.
  • the metal particle sintered layer includes carbon nanotubes or carbon nanoparticles, and the fine gas introduction path is formed by burning the carbon nano nanotubes or carbon nanoparticles by burning the metal particle sintered layer in the atmosphere. It may be formed.
  • the metal particle sintered layer may include ZnO, and the fine gas introduction path may be formed by etching ZnO by wet etching after burning the metal particle sintered layer in the atmosphere.
  • the metal particles of the metal particle sintered layer may include any one of Pt, Ag, Pd, Au, or Ru.
  • the metal particle sintered layer may include nanowires that are confined in the metal particle sintered layer and are not burned by combustion in the atmosphere.
  • the nanowire or nanoparticle has a diameter of about 0.1 ⁇ m or less.
  • the length of the nanowire is, for example, about 10 ⁇ m or less.
  • the merit of using the nanowire is that the gas permeation amount can be controlled by the shape (diameter and length) of the nanowire, and the gas permeation amount can be controlled by the ratio of the nanowire.
  • the limiting current type gas sensor 1A according to the tenth embodiment can control the gas permeation amount by the shape of the fine gas introduction path of the porous electrode 5D. Moreover, the limiting current type gas sensor 1A according to the tenth embodiment can control the gas permeation amount by the content ratio of the fine gas introduction path of the porous electrode 5D.
  • the limiting current gas sensor 1A has an insulating layer (for example, 0 0) disposed on the substrate 12 having the MEMS beam structure. .5 ⁇ m thick SiON film) 1a, and at least between the insulating layer 1a and the insulating layer 3 in the sensor portion, a heating microheater 2 is embedded in the same layer as the electrode layers 2a and 2a.
  • the microheater 2 is a polysilicon layer (polysilicon heater) having a thickness of about 0.3 ⁇ m, and has a resistance value of about 300 ⁇ by ion implantation.
  • the microheater 2 heats the solid electrolyte layer 4 by applying a predetermined voltage between the heater electrode portions 9a and 9a.
  • the micro heater 2 can also be formed by a Pt heater formed by printing.
  • the limiting current gas sensor 1A uses a beam structure (open structure) having a MEMS structure as a basic structure, thereby reducing the heat capacity of the sensor portion and improving the sensor sensitivity. .
  • the microheater 2 is disposed between the substrate 12 as the sensor portion and the porous electrode 5D with the insulating layers 1a and 3 interposed therebetween. Not limited to this, it may be disposed on the lower surface of the insulating layer 1a facing the surface on which the porous electrode 5D is formed, or on the lower portion of the substrate 12.
  • the microheater 2 may be embedded in the substrate 12.
  • a silicon oxide film / silicon nitride film laminated film (not shown) including the microheater 2 made of polysilicon may be formed on the surface of the substrate 12.
  • a detection voltage supplied to the dense electrode 5U and the porous electrode 5D Is applied between the detection terminals 9b and 9b, thereby connecting a detection circuit 107 for detecting a predetermined gas concentration in the gas to be measured by a limiting current type.
  • the detection circuit 107 can detect the oxygen concentration based on the limit current.
  • the detection circuit 107 can detect the water vapor concentration based on the limit current.
  • the heater electrode portions 9a and 9a and the detection terminals 9b and 9b are arranged so that their directions are substantially orthogonal to each other.
  • the aspect ratio of the gas diffusion path 15 can be increased, so that the sensor characteristics can be easily improved.
  • the manufacturing method of the limiting current type gas sensor 1A according to the tenth embodiment includes a step of forming the porous electrode 5D through the insulating layer 3 in a region on the substrate 12 corresponding to the sensor portion, and the porous electrode 5D.
  • FIGS. 149 (a) and 149 (b) the manufacturing method of the limiting current type gas sensor 1A according to the tenth embodiment shown in FIGS. 149 (a) and 149 (b) is expressed as shown in FIGS.
  • the case where the path 15a is formed will be described.
  • a silicon substrate 12 having a thickness of about 10 ⁇ m is prepared, and an upper surface of the substrate 12 is formed by plasma CVD (P-CVD).
  • An insulating layer 1a made of a SiON film having a thickness of 0.5 ⁇ m is formed.
  • a polysilicon layer having a thickness of about 0.3 ⁇ m is formed on the insulating layer 1a, and the polysilicon layer is etched or the like. Patterning is performed to form the microheater 2 and electrode layers 2a and 2a and electrode layers 2b and 2b connected to the microheater 2.
  • the electrode layers 2a and 2a and the electrode layers 2b and 2b are formed at positions orthogonal to each other.
  • the microheater 2 is formed so that the width between the electrode layers 2a and 2a is about 300 ⁇ m.
  • the concentration of the microheater 2 is set so that the resistance value between the electrode layers 2 a and 2 a is 300 ⁇ by ion implantation, and the electrode layers 2 a and 2 a and the electrode layers 2 b and 2 b are higher than the microheater 2. Formed (implanted) to a concentration.
  • SiON film (first insulating film) of about 0.5 ⁇ m thick by P-CVD method on the entire surface to form a 3 1.
  • the length (L) including the opening 15c is 400 ⁇ m, the width (W) is 30 ⁇ m, and the thickness (depth (D)) is 0.1 ⁇ m.
  • the predetermined aspect ratio of the gas diffusion path 15 can be easily increased by increasing the flow path length of the gas flow path 15a or decreasing the cross-sectional area (flow path cross-sectional area) of the gas flow path 15a.
  • the sensor characteristics can be improved by increasing the aspect ratio of the gas diffusion path 15.
  • 19b is deposited to have a thickness of about 0.5 ⁇ m
  • the inlet forming film 19c for forming the gas inlet 15c is formed to have a thickness of about 0.5 ⁇ m so as to overlap the other end side of the flow path forming film 19a.
  • Inlet formed film 19b and the introduction port forming layer 19c are both etching selectivity is different from the film forming member is formed using, for example, a polysilicon film and the SiON film 3 1 which constitutes the insulating layer 3.
  • the intake port forming film 19b and the inlet port forming film 19c are formed in a circular shape having a diameter of, for example, about 50 ⁇ m and are formed so as to overlap both ends of the flow path forming film 19a, so that the length (L) is increased.
  • a 300 ⁇ m gas flow path 15 a can be formed.
  • the formation of the flow path forming film 19a, the intake port forming film 19b, and the inlet port forming film 19c for forming these gas diffusion paths 15 is performed before the porous electrode 5D is formed.
  • the polysilicon film is etched so that it is flush with the upper surfaces of the intake port forming film 19b and the inlet port forming film 19c.
  • film forming member selected ratios are different, for example, a SiON film (second insulating film) 3 2 by embedding the upper passage-forming layer 19a.
  • SiON film 3 2 constituting the insulating layer 3 is entirely depot so as to have a thickness of about 0.6 ⁇ m by P-CVD method.
  • the insides of the openings 3a and 3a, the openings 3b and 3b, and the openings 3c and 3c are made of, for example, a Pt / Ti laminated film.
  • the heater electrode portions 9a and 9a, the detection terminals 9b and 9b, and the connection terminals 9c and 9c made of a laminated film of a Ti film and a Pt film are formed.
  • a Ti film having a thickness of 20 nm is formed along the side wall and the bottom, and a part thereof is on the insulating layer 3.
  • a Pt film having a thickness of 100 nm may be embedded therein so as to cover the protrusion and the insulating layer 3.
  • the porous electrode 5D made of a porous Pt film having a thickness of about 100 nm is formed with a width of about 200 ⁇ m (along the gas diffusion path 15) by sputtering or the like.
  • the upper end of the introduction port forming film 19c exposed to the surface of the insulating layer 3 is closed, and the extension end of the porous electrode 5D extending from the sensor portion is connected to one connection terminal 9c.
  • a solid electrolyte layer 4 made of a YSZ film is formed to a thickness of about 1 ⁇ m by sputtering.
  • the solid electrolyte layer 4 With a width of about 250 ⁇ m (the length in the direction along the gas diffusion path 15), for example, the extended end side of the porous electrode 5D connected to one connection terminal 9c of the sensor portion The periphery of the porous electrode 5D is covered.
  • the substrate 12 corresponding to the sensor portion is selectively deep-etched, and the substrate 12 having the MEMS beam structure is formed in the cavity C (Cavity: A cavity) is formed in an open type structure formed in an open structure.
  • the cavity C depends on the size of the limiting current gas sensor 1A according to the tenth embodiment, but the length in the direction perpendicular to the gas diffusion path 15 ⁇ the length in the direction along the gas diffusion path 15 is 500 ⁇ m. ⁇ 400 ⁇ m is desirable.
  • the polysilicon film constituting the flow path forming film 19a, the intake port forming film 19b, and the inlet forming film 19c for forming the gas diffusion path 15 is selectively formed by, for example, wet etching.
  • the limiting current type gas sensor 1A according to the tenth embodiment having the configuration shown in FIGS. 149 (a) and 149 (b) is obtained.
  • the gas channel 15a has a longer channel length, or the gas channel 15a has a smaller sectional area (channel sectional area).
  • the aspect ratio of the gas diffusion path 15 can be easily increased, so that the sensor characteristics can be easily improved.
  • the gas diffusion path 15 having a large aspect ratio can be accurately (accurately) formed, so that the sensor characteristics can be further stabilized.
  • the gas introduction port 15c is arranged at substantially the center of the sensor portion.
  • the gas intake port 15b can be freely arranged anywhere in the region of the non-sensor portion. It is easy to form the gas flow path 15a having a path length.
  • FIG. 162 (a) A schematic planar pattern configuration of the limiting current type gas sensor 2A according to the eleventh embodiment is expressed as shown in FIG. 162 (a), and is taken along the IIA-IIA line in FIG. 162 (a).
  • Mechanical Systems A schematic cross-sectional structure of the sensor 2A formed in the beam structure is expressed as shown in FIG. 162 (b).
  • the limiting current type gas sensor 2A includes a substrate 12 having a MEMS beam structure in which the limit according to the tenth embodiment described above.
  • the other configurations are the same, and therefore, redundant description will be omitted as much as possible, and the manufacturing method will be described in more detail.
  • the limiting current type gas sensor 2A includes a MEMS beam structure substrate 12 in which a cavity C has a ship-type structure, and a central portion.
  • a porous electrode (porous Pt electrode) 5D disposed on the substrate 12
  • a solid electrolyte layer (YSZ film) 4 disposed so as to cover the porous electrode 5D
  • a dense electrode (porous Pt electrode) 5U disposed substantially in the vertical direction with respect to the substrate 12 is provided.
  • the limiting current type gas sensor 2A has an insulating layer 3 on almost the entire surface, and a gas to be measured (via a gas diffusion path 15 formed on the upper layer portion of the insulating layer 3 with a predetermined aspect ratio (for example, O 2 gas) is introduced toward the sensor portion.
  • a gas to be measured via a gas diffusion path 15 formed on the upper layer portion of the insulating layer 3 with a predetermined aspect ratio ( For example, O 2 gas) is introduced toward the sensor portion.
  • the limit current type gas sensor 2A according to the eleventh embodiment can easily improve the sensor characteristics by increasing the aspect ratio of the gas diffusion path 15, and the gas diffusion path 15 can be accurately formed. The sensor characteristics can be further stabilized.
  • a silicon substrate 12 having a thickness of about 10 ⁇ m is prepared, and the upper surface of the substrate 12 is formed in accordance with the part where the cavity C of the ship structure is formed.
  • the polysilicon film 1b having a different etching selectivity from the substrate 12 is deposited so as to have a thickness of about 0.1 ⁇ m.
  • a SiON film having an etching selectivity different from that of the polysilicon film 1b is deposited by P-CVD, and an insulating layer 1a having a thickness of about 0.5 ⁇ m is formed on the upper surface of the substrate 12.
  • a polysilicon layer having a thickness of about 0.3 ⁇ m is formed on the insulating layer 1a, and the polysilicon layer is etched or the like. Patterning is performed to form the microheater 2, the electrode layers 2a and 2a connected to the microheater 2, and the electrode layers 2b and 2b. The electrode layers 2a and 2a and the electrode layers 2b and 2b are formed at positions orthogonal to each other.
  • the concentration of the microheater 2 is set so that the resistance value between the electrode layers 2 a and 2 a is 300 ⁇ by ion implantation, and the electrode layers 2 a and 2 a and the electrode layers 2 b and 2 b are higher than the microheater 2. Formed (implanted) to a concentration.
  • SiON film first insulating film of about 0.5 ⁇ m thick by P-CVD method on the entire surface to form a 3 1.
  • Flow channel forming film 19a is etching selectivity is formed by using the film forming member, such as a different polysilicon film and the SiON film 3 1.
  • (L) is 400 ⁇ m
  • width (W) is 30 ⁇ m
  • thickness (depth (D)) is 0.1 ⁇ m.
  • the predetermined aspect ratio of the gas diffusion path 15 can be easily increased by increasing the flow path length of the gas flow path 15a or decreasing the cross-sectional area (flow path cross-sectional area) of the gas flow path 15a.
  • the sensor characteristics can be improved by increasing the aspect ratio of the gas diffusion path 15.
  • a circular gas inlet 15b having a diameter of about 50 ⁇ m is formed so as to overlap the one end side of the flow path forming film 19a.
  • the inlet forming film 19b to be formed is deposited so as to have a thickness of about 0.5 ⁇ m, and a circular gas having a diameter of, for example, about 50 ⁇ m so as to overlap the other end side of the flow path forming film 19a.
  • the introduction port forming film 19c for forming the introduction port 15c is deposited so as to have a thickness of about 0.5 ⁇ m.
  • Inlet formed film 19b and the introduction port forming layer 19c are both etching selectivity is different from the film forming member is formed using, for example, a polysilicon film and the SiON film 3 1 which constitutes the insulating layer 3.
  • the intake port forming film 19b and the inlet port forming film 19c are formed before the porous electrode 5D is formed.
  • a poly-polyoxide is formed by P-CVD so as to be the same height as the upper surfaces of the intake port forming film 19b and the inlet port forming film 19c.
  • silicon film as an etching selection ratio is different film forming member, fully and depot, for example, a SiON film (second insulating film) 3 2 a thickness of about 0.6 .mu.m, embedding the upper flow channel forming film 19a.
  • the insulating layer 3 is selectively removed, and about four openings 17 having a depth reaching the polysilicon film 1b are formed.
  • the openings 17 are preferably formed, for example, in the vicinity of the four corners of the polysilicon film 1b in order to perform wet etching described later efficiently.
  • the insides of the openings 3a and 3a, the openings 3b and 3b, and the openings 3c and 3c are made of, for example, a Pt / Ti laminated film.
  • the heater electrode portions 9a and 9a, the detection terminals 9b and 9b, and the connection terminals 9c and 9c made of a laminated film of a 20 nm thick Ti film and a 100 nm thick Pt film are formed.
  • a porous electrode 5D made of a porous Pt film having a thickness of about 100 nm is formed by sputtering or the like, and is exposed on the surface of the insulating layer 3.
  • the upper surface of the introduction port forming film 19c is closed, and the extended end of the porous electrode 5D extending from the sensor portion is connected to one connection terminal 9c.
  • a solid electrolyte layer 4 made of a YSZ film is formed with a thickness of about 1 ⁇ m by sputtering, and one connection terminal 9c of the sensor portion is formed.
  • the periphery of the porous electrode 5D is covered except for the extending end side of the porous electrode 5D connected to the.
  • the polysilicon film constituting the flow path formation film 19a, the intake port formation film 19b, and the introduction port formation film 19c for forming the gas diffusion path 15 is selectively selected by wet etching, for example.
  • the polysilicon film 1b and the underlying substrate 12 are selectively removed through the opening 17, thereby having the configuration shown in FIGS. 162 (a) and 162 (b).
  • the limiting current type gas sensor 2A according to the eleventh embodiment is obtained.
  • the limiting current type gas sensor 2A includes the gas diffusion path 15 having a predetermined aspect ratio and introducing the gas to be measured toward the sensor portion in the upper layer portion of the insulating layer 3.
  • the substrate 12 having the MEMS beam structure is formed to have a ship-shaped structure in which a cavity C (cavity) is formed in a ship shape in the substrate 12 corresponding to the sensor portion.
  • the flow path length of the gas flow path 15a is increased, or the cross-sectional area (flow path cross-sectional area) of the gas flow path 15a is decreased.
  • the aspect ratio of the gas diffusion path 15 can be easily increased, so that the sensor characteristics can be easily improved.
  • the gas diffusion path 15 having a large aspect ratio can be accurately formed, so that the sensor characteristics can be further stabilized.
  • the gas introduction port 15c is arranged at substantially the center of the sensor portion.
  • the gas intake port 15b can be freely arranged anywhere in the region of the non-sensor portion. It is easy to form the gas flow path 15a having a path length.
  • FIG. 174 (a) A schematic planar pattern configuration of the limiting current type gas sensor 3A according to the twelfth embodiment is expressed as shown in FIG. 174 (a), and is taken along the line IIIA-IIIA in FIG. 174 (a).
  • Mechanical Systems A schematic cross-sectional structure of the sensor 3A formed in the beam structure is expressed as shown in FIG. Again, overlapping descriptions are omitted as much as possible, and the characteristic portions will be described in more detail.
  • the limiting current type gas sensor 3A corresponds to the MEMS beam structure substrate 12 and the center sensor portion, as shown in FIGS. 174 (a) and 174 (b).
  • the porous electrode (porous Pt electrode) 5D disposed on the substrate 12, the solid electrolyte layer (YSZ film) 4 disposed so as to cover the porous electrode 5D, and the solid electrolyte facing the porous electrode 5D
  • a dense electrode (porous Pt electrode) 5U disposed substantially vertically with respect to the substrate 12 and a lid 110 provided on the substrate 12 so as to surround the region of the sensor portion are provided.
  • the limiting current type gas sensor 3A introduces a gas to be measured (for example, O 2 gas) toward the sensor portion via a gas diffusion path 115 formed in the lid 110 with a predetermined aspect ratio. Is configured to do.
  • a gas to be measured for example, O 2 gas
  • the gas to be measured introduced into the sensor portion passes through the gas lead-out path 40 provided in the insulating layers 1a and 3 on the substrate 12 side. To the cavity C side.
  • the limiting current type gas sensor 3A includes a substrate 12, a porous electrode 5D disposed in the region of the sensor portion on the substrate 12 via the insulating layer 3, and a porous electrode 5D.
  • the gas diffusion path 115 is introduced into the lid 110, and the gas diffusion path 115 is formed in the lid 110 further provided.
  • the gas diffusion path 115 includes a gas intake port 115b that takes in the gas to be measured, a gas introduction port 115c that introduces the gas to be measured, and a gas flow channel (micro flow channel) that connects the gas introduction port 115c and the gas intake port 115b.
  • 115a, and the flow rate of the gas to be measured can be controlled in accordance with the aspect ratio (ratio between the channel length of the microchannel and the channel cross-sectional area).
  • the lid 110 is formed so as to expose the heater electrode portions 9a and 9a and the detection terminals 9b and 9b on the insulating layer 3, and a space region (Cavity) provided according to the region of the sensor portion. Has CAa.
  • the gas introduction port 115 c is provided in the ceiling portion of the space region CAa in the lid body 110, and the gas intake port 115 b is provided in the non-sensor portion region of the upper surface portion of the lid body 110. Yes. And, between the gas intake port 115b and the gas introduction port 115c, for example, via a plurality of linear gas flow paths 115a (115a -1 , 115a -2 , 115a -3 ) included in a U-shape. Connected almost horizontally.
  • the gas lead-out path 40 has an opening structure in which the insulating layer 3, the microheater 2, and the insulating layer 1a at the substantially central portion of the sensor portion are opened at a depth reaching the cavity C of the substrate 12 having the MEMS beam structure.
  • the first opening 40a has a large diameter and the second opening 40b has a small diameter.
  • the limiting current type gas sensor 3A includes a gas diffusion path 115 formed with a predetermined aspect ratio on a lid 110 attached by bonding onto a substrate 12 having a MEMS beam structure.
  • a gas diffusion path 115 formed with a predetermined aspect ratio on a lid 110 attached by bonding onto a substrate 12 having a MEMS beam structure.
  • the manufacturing method of the limiting current type gas sensor 3A includes a step of forming the porous electrode 5D through the insulating layer 3 in a region on the substrate 12 corresponding to the sensor portion, and the porous electrode 5D.
  • a step of forming the solid electrolyte layer 4 on the upper surface portion a step of forming the dense electrode 5U on the surface of the solid electrolyte layer 4 facing the porous electrode 5D, a predetermined aspect ratio, and a gas to be measured.
  • a silicon substrate 12 having a thickness of about 10 ⁇ m is prepared, and about 0.1 ⁇ m is formed on the upper surface of the substrate 12 by plasma CVD (P-CVD).
  • An insulating layer 1a made of a 5 ⁇ m thick SiON film is formed.
  • a polysilicon layer having a thickness of about 0.3 ⁇ m is formed on the insulating layer 1a, and the polysilicon layer is etched or the like. Patterning is performed to form the microheater 2, the electrode layers 2a and 2a connected to the microheater 2, and the electrode layers 2b and 2b. The electrode layers 2a and 2a and the electrode layers 2b and 2b are formed at positions orthogonal to each other. The microheater 2 is formed so that the width between the electrode layers 2a and 2a is about 300 ⁇ m.
  • the concentration of the microheater 2 is set so that the resistance value between the electrode layers 2 a and 2 a is 300 ⁇ by ion implantation, and the electrode layers 2 a and 2 a and the electrode layers 2 b and 2 b are higher than the microheater 2. Formed (implanted) to a concentration.
  • a circular opening 40A having a diameter of about 50 ⁇ m is formed at a depth reaching the insulating layer 1a in the center of the sensor portion of the microheater 2, for example.
  • an insulating layer 3 made of a SiON film having a thickness of about 0.5 ⁇ m is uniformly formed on the entire surface by P-CVD.
  • the insulating layer 3 is embedded on the insulating layer 1a in the portion 40A, and a recess serving as the first opening 40a of the gas outlet path 40 is formed on the upper surface thereof.
  • the depth of the first opening 40a is about 0.3 ⁇ m depending on the thickness of the polysilicon layer (microheater 2).
  • FIGS. 178 (a) and 178 (b) Next, as shown in FIGS. 178 (a) and 178 (b), the insulating layer 3 embedded in the bottom surface of the first opening 40a and the insulating layer 1a therebelow are removed by etching.
  • the depth of the second opening 40b is about 1 ⁇ m depending on the thickness of the insulating layers 1a and 3.
  • the insides of the openings 3a and 3a, the openings 3b and 3b, and the openings 3c and 3c are made of, for example, a Pt / Ti laminated film.
  • the heater electrode portions 9a and 9a, the detection terminals 9b and 9b, and the connection terminals 9c and 9c made of a laminated film of a Ti film and a Pt film are formed.
  • a Ti film having a thickness of 20 nm is formed along the side wall and the bottom, and a part thereof is on the insulating layer 3.
  • a Pt film having a thickness of 100 nm may be embedded therein so as to cover the protrusion and the insulating layer 3.
  • a porous electrode 5D made of a porous Pt film having a thickness of about 100 nm is formed by sputtering or the like, and is exposed on the surface of the insulating layer 3.
  • the upper surface of the polysilicon film 27 is closed, and the extended end of the porous electrode 5D extending from the sensor portion is connected to one connection terminal 9c.
  • a solid electrolyte layer 4 made of a YSZ film is formed to a thickness of about 1 ⁇ m by sputtering, and one connection terminal 9c of the sensor portion is formed.
  • the periphery of the porous electrode 5D is covered except for the extending end side of the porous electrode 5D connected to the.
  • the substrate 12 corresponding to the sensor portion is selectively deep-etched, and the substrate 12 having the MEMS beam structure is formed in the cavity C (Cavity: A cavity) is formed in an open type structure formed in an open structure.
  • the gas outlet path 20 is formed by selectively removing the polysilicon film 27 embedded in the first opening 40a and the second opening 40b by, for example, wet etching.
  • FIG. 186 (a) A schematic plane pattern configuration of a limiting current gas sensor 4A according to a first modification of the twelfth embodiment is expressed as shown in FIG. 186 (a), and is along the line IVA-IVA in FIG. 186 (a).
  • FIG. 186 (b) A schematic cross-sectional structure of the sensor 4A formed in a MEMS (Micro Electro Mechanical Systems) beam structure is expressed as shown in FIG. 186 (b).
  • MEMS Micro Electro Mechanical Systems
  • the limiting current type gas sensor 4A includes a MEMS beam structure substrate 12 and a central sensor.
  • a porous electrode (porous Pt electrode) 5D disposed on the substrate 12, a solid electrolyte layer (YSZ film) 4 disposed so as to cover the porous electrode 5D, and a porous electrode 5D
  • a dense electrode (porous Pt electrode) 5U disposed substantially vertically with respect to the substrate 12 on the solid electrolyte layer 4 opposite to the substrate 12 and a lid body 112 provided on the substrate 12 so as to surround a region of the sensor portion.
  • the limiting current type gas sensor 4A introduces a gas to be measured (for example, O 2 gas) toward the sensor portion through a gas diffusion path 116 formed in the lid body 112 with a predetermined aspect ratio. Is configured to do.
  • a gas to be measured for example, O 2 gas
  • the limiting current type gas sensor 4A includes a substrate 12 and a porous electrode 5D disposed in the region of the sensor portion on the substrate 12 via the insulating layer 3.
  • a solid electrolyte layer 4 disposed on the upper surface of the porous electrode 5D; a dense electrode 5U disposed on the surface of the solid electrolyte layer 4 facing the porous electrode 5D; and a predetermined aspect ratio;
  • the gas diffusion path 116 for introducing the measurement gas toward the sensor portion is provided, and the gas diffusion path 116 is formed on the lid body 112 further provided.
  • the gas diffusion path 116 provided in the lid 112 introduces the gas to be measured and the gas inlet 116a for taking in the gas to be measured.
  • Gas inlet 116b, and a gas channel (microchannel) 116c that connects gas inlet 116b and gas inlet 116a, and has an aspect ratio (the channel length of the microchannel and the channel cross-sectional area). The flow rate of the gas to be measured can be controlled according to the ratio.
  • the gas introduction port 116 b is provided in the ceiling portion of the space region CAa in the lid body 112, and the gas intake port 116 a is provided in the region of the non-sensor portion on the upper surface portion of the lid body 112. It has been.
  • the gas inlet 116a and the gas inlet 116b are connected in a substantially horizontal direction via, for example, a straight gas flow path 116c.
  • a silicon substrate (first lid member) 112a having a thickness of about 10 ⁇ m is prepared, and the gas diffusion path 116 on the surface side is prepared.
  • a flow path forming film 112b for forming the gas flow path 116c is formed (deposit + patterning) at the site to be formed.
  • one end of the flow path forming film 112b corresponds to the region of the non-sensor portion, and the other end corresponds to the substantially central portion of the sensor portion.
  • the length (L) not including the opening 116b is 300 ⁇ m, the width (W) is 30 ⁇ m, and the thickness (depth (D)) is 0.1 ⁇ m.
  • the predetermined aspect ratio of the gas diffusion path 116 can be easily increased by increasing the flow path length of the gas flow path 116c or decreasing the cross-sectional area (flow path cross-sectional area) of the gas flow path 116c.
  • the sensor characteristics can be improved by increasing the aspect ratio of the gas diffusion path 116.
  • a film forming member having a different etching selectivity from the SiO 2 film for example, a polysilicon film (second lid member) 112c is formed on the entire surface. Deposit and embed the flow path forming film 112b.
  • the gas intake port 116a and the gas introduction port 116b are formed in a circular shape with a diameter of about 50 ⁇ m, for example, and are formed at both ends of the flow channel forming film 112b so that the flow channel length of the gas flow channel 116c is 300 ⁇ m. Is done.
  • the length of the gas flow path 116c is increased or the cross-sectional area of the gas flow path 116c (flow path cut-off) is increased.
  • the aspect ratio of the gas diffusion path 116 can be easily increased, so that the sensor characteristics can be easily improved.
  • the gas diffusion path 116 having a large aspect ratio can be accurately formed, so that the sensor characteristics can be further stabilized.
  • FIG. 193 (a) A schematic planar pattern configuration of a limit current gas sensor 5A according to a second modification of the twelfth embodiment is represented as shown in FIG. 193 (a), and is along the line VA-VA in FIG. 193 (a).
  • FIG. 193 (b) A schematic cross-sectional structure of the sensor 5A formed in a MEMS (Micro Electro Mechanical Systems) beam structure is expressed as shown in FIG. 193 (b).
  • MEMS Micro Electro Mechanical Systems
  • the limiting current type gas sensor 5A includes the MEMS beam substrate 12 and the central sensor.
  • a porous electrode (porous Pt electrode) 5D disposed on the substrate 12, a solid electrolyte layer (YSZ film) 4 disposed so as to cover the porous electrode 5D, and a porous electrode 5D
  • a dense electrode (porous Pt electrode) 5U disposed substantially vertically with respect to the substrate 12 on the solid electrolyte layer 4 opposite to the substrate 12 and a lid 113 provided on the substrate 12 so as to surround a region of the sensor portion.
  • the limiting current type gas sensor 5A introduces a gas to be measured (for example, O 2 gas) toward the sensor portion via a gas diffusion path 117 formed in the lid body 113 with a predetermined aspect ratio. Is configured to do.
  • a gas to be measured for example, O 2 gas
  • the limiting current type gas sensor 5A includes a substrate 12 and a porous electrode 5D disposed in the region of the sensor portion on the substrate 12 via the insulating layer 3.
  • a solid electrolyte layer 4 disposed on the upper surface of the porous electrode 5D; a dense electrode 5U disposed on the surface of the solid electrolyte layer 4 facing the porous electrode 5D; and a predetermined aspect ratio;
  • the gas diffusion path 117 for introducing the measurement gas toward the sensor portion is provided, and the gas diffusion path 117 is formed in the lid 113 further provided.
  • the gas diffusion path 117 provided in the lid 113 introduces the gas to be measured and the gas intake port 117a for taking in the gas to be measured.
  • Gas inlet 117b, and gas channel (microchannel) 117c that connects gas inlet 117b and gas intake port 117a, and has an aspect ratio (the channel length of the microchannel and the channel cross-sectional area). The flow rate of the gas to be measured can be controlled according to the ratio.
  • the gas diffusion path 117 is provided in a substantially vertical direction, for example, in the substantially central portion of the sensor portion, in the ceiling portion of the space area CAa in the lid 113, and between the gas intake port 117a and the gas inlet port 117b. They are connected in a straight line via the gas flow path 117c.
  • the aspect ratio of the gas diffusion path 117 can be easily controlled by adjusting the diameter of the gas flow path 117c (the diameter of the flow path forming film) and the flow path length (the thickness of the polysilicon film), for example.
  • the flow path length of the gas flow path 117c is increased, or the cross-sectional area (flow path cross-sectional area) of the gas flow path 117c is decreased.
  • the aspect ratio of the gas diffusion path 117 can be easily increased, so that the sensor characteristics can be easily improved.
  • the gas diffusion path 117 having a large aspect ratio can be accurately formed, so that the sensor characteristics can be further stabilized.
  • FIG. 194 (a) A schematic planar pattern configuration of a limiting current type gas sensor 6A according to a third modification of the twelfth embodiment is expressed as shown in FIG. 194 (a) and is along the line VIA-VIA of FIG. 194 (a).
  • FIG. 194 (b) A schematic cross-sectional structure of the sensor 6A formed in a MEMS (Micro Electro Mechanical Systems) beam structure is expressed as shown in FIG. 194 (b).
  • MEMS Micro Electro Mechanical Systems
  • the limiting current type gas sensor 6A includes the MEMS beam substrate 12 and the central sensor.
  • a porous electrode (porous Pt electrode) 5D disposed on the substrate 12, a solid electrolyte layer (YSZ film) 4 disposed so as to cover the porous electrode 5D, and a porous electrode 5D
  • a dense electrode (porous Pt electrode) 5U disposed substantially vertically with respect to the substrate 12 on the solid electrolyte layer 4 opposite to the substrate 12 and a lid 114 provided on the substrate 12 so as to surround a region of the sensor portion.
  • the limiting current type gas sensor 6A introduces a gas to be measured (for example, O 2 gas) toward the sensor portion through a gas diffusion path 118 formed in the lid body 114 with a predetermined aspect ratio. Is configured to do.
  • a gas to be measured for example, O 2 gas
  • the limiting current type gas sensor 6A includes a substrate 12 and a porous electrode 5D disposed in the region of the sensor portion on the substrate 12 via the insulating layer 3.
  • a solid electrolyte layer 4 disposed on the upper surface of the porous electrode 5D; a dense electrode 5U disposed on the surface of the solid electrolyte layer 4 facing the porous electrode 5D; and a predetermined aspect ratio;
  • the gas diffusion path 118 for introducing the measurement gas toward the sensor portion is provided, and the gas diffusion path 118 is formed in the lid body 114 further provided.
  • the gas diffusion path 118 provided in the lid 114 introduces the gas to be measured, the gas intake port 118a for taking in the gas to be measured.
  • the gas introduction port 118b is provided in the ceiling portion of the space area CAa in the lid 114, and the gas intake port 118a is provided in the side surface of the lid 114.
  • the gas intake port 118a and the gas inlet port 118b are connected in a substantially horizontal direction via, for example, a straight gas flow path 118c.
  • the flow path length of the gas flow path 118c is increased, or the cross-sectional area (flow path cross-sectional area) of the gas flow path 118c is decreased.
  • the aspect ratio of the gas diffusion path 118 can be easily increased, so that the sensor characteristics can be easily improved.
  • the gas diffusion path 118 having a large aspect ratio can be accurately formed, so that the sensor characteristics can be further stabilized.
  • gas diffusion path 118 can also be formed so as to be drawn out in one of the oblique directions corresponding to the four corners of the lid 114.
  • the method for manufacturing the limiting current type gas sensors 1A to 6A according to the tenth to twelfth embodiments may include a step of forming the microheater 2 on the upper part of the substrate 12 or on the lower part of the substrate 12.
  • the method for manufacturing the limiting current gas sensors 1A to 6A according to the tenth to twelfth embodiments may include a step of forming the microheater 2 embedded in the substrate 12.
  • the microheater 2 In the method for manufacturing the limiting current type gas sensors 1A to 6A according to the tenth to twelfth embodiments, the microheater 2, the insulating layer 3, the porous electrode 5D, the dense electrode 5U, and the solid electrolyte layer 4 are formed in the printing process. Can be formed.
  • the operation of detecting the gas concentration is the limiting current type gas sensor according to the first to sixth embodiments as described above. Since this is substantially the same as the case of, detailed description is omitted.
  • the description of the electrochemical reaction is substantially the same as the case of the limiting current type gas sensor according to the first to sixth embodiments as described above, and thus detailed description thereof is omitted.
  • the package is substantially the same as that of the limiting current type gas sensor according to the first to sixth embodiments, and thus detailed description thereof is omitted.
  • the configuration example of the sensor node using the energy harvester power supply is substantially the same as the case of the limiting current type gas sensor according to the first to sixth embodiments described above, and detailed description thereof is omitted.
  • the schematic block configuration of the sensor package is substantially the same as that of the limit current gas sensors according to the first to sixth embodiments described above. The detailed description is omitted.
  • the schematic block configuration of the sensor network system to which the limit current type gas sensor according to the tenth to twelfth embodiments is applied is the same as the case of the limit current type gas sensor according to the first to sixth embodiments described above. Since it is substantially the same, detailed description here is abbreviate
  • the present embodiment it is possible to easily and precisely form a gas diffusion path having a large aspect ratio by using the etching selection ratio. As a result, the sensor characteristics can be improved and the sensor can be improved. It is possible to provide a limiting current type gas sensor capable of further stabilizing the characteristics.
  • each embodiment includes various aspects not described here. For example, it is possible to detect the concentration of carbon dioxide by replacing zirconia with other materials or combining several materials.
  • the limiting current type gas sensor of the present embodiment can be applied to an oxygen sensor and a humidity sensor. Further, such a sensor can be applied to automobile exhaust gas and sensor networks.
  • Electrode layer 2b Detection terminal (electrode layer) 3 1 ... SiON film (first insulating film) 3 2 ... SiON film (second insulating film) 3a, 3b, 3c, 7, 17, 37, 45 ... opening 4, 30, 106 ... solid electrolyte layer (YSZ, YSZ thin film) 5D, 5D 1 , 5D 2 , 105D ... porous electrode (Ti / Pt electrode, porous Pt, anode) 5U, 5U 1 , 5U 2 ...

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Biochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Molecular Biology (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
  • Measuring Oxygen Concentration In Cells (AREA)

Abstract

L'invention concerne un capteur de gaz de type à courant limite (1A) comprenant : un substrat (12) ; un microdispositif de chauffage MH qui est disposé sur le substrat (12) avec une première couche isolante (181) entre ceux-ci ; un chemin d'introduction de gaz (51) qui est disposé sur le microdispositif de chauffage MH avec une deuxième couche isolante (182) entre ceux-ci, et qui reçoit un gaz à mesurer ; une électrode inférieure (28D) qui est disposée sur le chemin d'introduction de gaz (51) ; une couche d'électrolyte solide (30) qui est disposée sur l'électrode inférieure (28D) ; une électrode supérieure (28U) qui est disposée sur une surface de la couche d'électrolyte solide (30) sur le côté opposé à celui de l'électrode inférieure (28D) ; et une section de cavité C qui est formée dans le substrat (12), ladite cavité étant sensiblement plus grande que le microdispositif de chauffage MH. On obtient un capteur de gaz de type à courant limite dont les caractéristiques sont améliorées et présentant une meilleure stabilité.
PCT/JP2016/069736 2015-07-21 2016-07-04 Capteur de gaz de type à courant limite WO2017014033A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2017529532A JP6730280B2 (ja) 2015-07-21 2016-07-04 限界電流式ガスセンサ

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP2015143925 2015-07-21
JP2015-143925 2015-07-21
JP2015-153297 2015-08-03
JP2015153297 2015-08-03
JP2016-067775 2016-03-30
JP2016067775 2016-03-30

Publications (1)

Publication Number Publication Date
WO2017014033A1 true WO2017014033A1 (fr) 2017-01-26

Family

ID=57835057

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2016/069736 WO2017014033A1 (fr) 2015-07-21 2016-07-04 Capteur de gaz de type à courant limite

Country Status (2)

Country Link
JP (1) JP6730280B2 (fr)
WO (1) WO2017014033A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020094831A (ja) * 2018-12-10 2020-06-18 日本特殊陶業株式会社 ガスセンサ素子の製造方法、ガスセンサ素子およびガスセンサ
US20210247353A1 (en) * 2020-02-10 2021-08-12 Rohm Co., Ltd. Limiting-current type gas sensor
US20220381724A1 (en) * 2021-05-31 2022-12-01 Rohm Co., Ltd. Gas sensor
WO2023167140A1 (fr) * 2022-03-02 2023-09-07 ローム株式会社 Système capteur
TWI818072B (zh) * 2018-10-15 2023-10-11 日商日寫股份有限公司 微機電系統氣體感測器及微機電系統氣體感測器的製造方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59166854A (ja) * 1983-03-14 1984-09-20 Toyota Central Res & Dev Lab Inc 限界電流式酸素センサ
JPH0735726A (ja) * 1993-07-21 1995-02-07 Yamatake Honeywell Co Ltd 気体成分検出素子
JP2000292395A (ja) * 1999-04-02 2000-10-20 Fuji Electric Co Ltd 薄膜ガスセンサ
JP2003075400A (ja) * 2001-08-31 2003-03-12 Yazaki Corp 限界電流式酸素センサ及び限界電流式酸素センサの出力制御方法
WO2014136329A1 (fr) * 2013-03-08 2014-09-12 ローム株式会社 Capteur de gaz à courant limite ainsi que procédé de fabrication de celui-ci, et système de réseau de capteur
WO2015166751A1 (fr) * 2014-05-02 2015-11-05 ローム株式会社 Capteur de gaz de type à courant de limitation, procédé de fabrication associé et système de réseau de capteurs

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59166854A (ja) * 1983-03-14 1984-09-20 Toyota Central Res & Dev Lab Inc 限界電流式酸素センサ
JPH0735726A (ja) * 1993-07-21 1995-02-07 Yamatake Honeywell Co Ltd 気体成分検出素子
JP2000292395A (ja) * 1999-04-02 2000-10-20 Fuji Electric Co Ltd 薄膜ガスセンサ
JP2003075400A (ja) * 2001-08-31 2003-03-12 Yazaki Corp 限界電流式酸素センサ及び限界電流式酸素センサの出力制御方法
WO2014136329A1 (fr) * 2013-03-08 2014-09-12 ローム株式会社 Capteur de gaz à courant limite ainsi que procédé de fabrication de celui-ci, et système de réseau de capteur
WO2015166751A1 (fr) * 2014-05-02 2015-11-05 ローム株式会社 Capteur de gaz de type à courant de limitation, procédé de fabrication associé et système de réseau de capteurs

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI818072B (zh) * 2018-10-15 2023-10-11 日商日寫股份有限公司 微機電系統氣體感測器及微機電系統氣體感測器的製造方法
JP2020094831A (ja) * 2018-12-10 2020-06-18 日本特殊陶業株式会社 ガスセンサ素子の製造方法、ガスセンサ素子およびガスセンサ
US20210247353A1 (en) * 2020-02-10 2021-08-12 Rohm Co., Ltd. Limiting-current type gas sensor
US11867656B2 (en) * 2020-02-10 2024-01-09 Rohm Co., Ltd. Limiting-current type gas sensor
US20220381724A1 (en) * 2021-05-31 2022-12-01 Rohm Co., Ltd. Gas sensor
WO2023167140A1 (fr) * 2022-03-02 2023-09-07 ローム株式会社 Système capteur

Also Published As

Publication number Publication date
JPWO2017014033A1 (ja) 2018-05-10
JP6730280B2 (ja) 2020-07-29

Similar Documents

Publication Publication Date Title
WO2017014033A1 (fr) Capteur de gaz de type à courant limite
JP6403985B2 (ja) 限界電流式ガスセンサおよびその製造方法、およびセンサネットワークシステム
KR100812996B1 (ko) 마이크로 가스 센서 및 그 제조방법
US10620153B2 (en) Nitrogen oxide based gas sensor, oxygen pump, gas sensor apparatus, manufacturing method of gas sensor apparatus, and sensor network system
US8961760B2 (en) Micromechanical solid-electrolyte sensor device and corresponding production method
TWI452287B (zh) 氣體感測元件及其製造方法
US4668374A (en) Gas sensor and method of fabricating same
WO2014136329A1 (fr) Capteur de gaz à courant limite ainsi que procédé de fabrication de celui-ci, et système de réseau de capteur
KR20090064693A (ko) 마이크로 가스 센서 및 그 제작 방법
US20170167999A1 (en) Semiconductor type gas sensor, method of manufacturing semiconductor type gas sensor, and sensor network system
US9354197B2 (en) Micromachined oxygen sensor and method of making the same
US10914700B2 (en) Single cantilever gas sensor, sensor array, and manufacturing method thereof
US20150097260A1 (en) Single Silicon Wafer Micromachined Thermal Conduction Sensor
ITMI20012128A1 (it) Elemento da costruzione micromeccanico e procedimento di fabbricazione
Radhakrishnan et al. Design, fabrication and characterization of a miniaturized series-connected potentiometric oxygen sensor
US20140290338A1 (en) Hydrogen gas sensor and method for manufacturing the same
JP2004514153A (ja) フローセンサ
Morata et al. Development and characterisation of a screen-printed mixed potential gas sensor
Iwata et al. Design, fabrication, and characterization of bridge-type micro-hotplates with an SU-8 supporting layer for a smart gas sensing system
US20060258037A1 (en) Method for producing a component having a semiconductor substrate and component
US20210239638A1 (en) Method for fabrication of mems integrated sensor and sensor thereof
Wang et al. Humidity Sensing of Ordered Macroporous Silicon With ${\rm HfO} _ {2} $ Thin-Film Surface Coating
TWI325054B (en) Gas sensor with diffuse micro cavity structure and method thereof
CN114646419B (zh) 一种气体压强传感器及其制备方法和气体压强检测方法
JP2016114511A (ja) 限界電流式ガスセンサ用電極およびその製造方法、限界電流式ガスセンサおよびその製造方法、およびセンサネットワークシステム

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16827595

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2017529532

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16827595

Country of ref document: EP

Kind code of ref document: A1