CN117269254B - Hydrogen sensor and preparation method thereof - Google Patents
Hydrogen sensor and preparation method thereof Download PDFInfo
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- CN117269254B CN117269254B CN202311554682.6A CN202311554682A CN117269254B CN 117269254 B CN117269254 B CN 117269254B CN 202311554682 A CN202311554682 A CN 202311554682A CN 117269254 B CN117269254 B CN 117269254B
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- 239000001257 hydrogen Substances 0.000 title claims abstract description 87
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 87
- 238000002360 preparation method Methods 0.000 title abstract description 10
- 125000004435 hydrogen atom Chemical class [H]* 0.000 title abstract 5
- 230000003197 catalytic effect Effects 0.000 claims abstract description 146
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims abstract description 28
- 229920005591 polysilicon Polymers 0.000 claims abstract description 25
- 230000035945 sensitivity Effects 0.000 claims abstract description 22
- 238000005452 bending Methods 0.000 claims description 84
- 150000002431 hydrogen Chemical class 0.000 claims description 51
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 17
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 14
- 238000009413 insulation Methods 0.000 claims description 14
- 229910052710 silicon Inorganic materials 0.000 claims description 14
- 239000010703 silicon Substances 0.000 claims description 14
- 239000000758 substrate Substances 0.000 claims description 14
- 238000009423 ventilation Methods 0.000 claims description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 10
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 10
- 238000000151 deposition Methods 0.000 claims description 9
- 238000005530 etching Methods 0.000 claims description 9
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 6
- 239000012528 membrane Substances 0.000 claims description 6
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 6
- WYTGDNHDOZPMIW-RCBQFDQVSA-N alstonine Natural products C1=CC2=C3C=CC=CC3=NC2=C2N1C[C@H]1[C@H](C)OC=C(C(=O)OC)[C@H]1C2 WYTGDNHDOZPMIW-RCBQFDQVSA-N 0.000 claims description 5
- 239000002131 composite material Substances 0.000 claims description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 10
- 229910052697 platinum Inorganic materials 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000007084 catalytic combustion reaction Methods 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- 239000010931 gold Substances 0.000 description 3
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000001312 dry etching Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000005468 ion implantation Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 241000208340 Araliaceae Species 0.000 description 1
- 235000005035 Panax pseudoginseng ssp. pseudoginseng Nutrition 0.000 description 1
- 235000003140 Panax quinquefolius Nutrition 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000010420 art technique Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 235000008434 ginseng Nutrition 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000004518 low pressure chemical vapour deposition Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000013022 venting Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
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
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/14—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature
- G01N27/16—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature caused by burning or catalytic oxidation of surrounding material to be tested, e.g. of gas
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
- B81C1/00023—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems without movable or flexible elements
- B81C1/00047—Cavities
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
- B81C1/00023—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems without movable or flexible elements
- B81C1/00055—Grooves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00349—Creating layers of material on a substrate
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
- B81C1/00523—Etching material
Abstract
The invention relates to a hydrogen sensor and a preparation method thereof, wherein a Wheatstone bridge of the hydrogen sensor comprises four bridge arms, a catalytic component and a reference component; the catalytic assembly comprises a first catalytic resistor and a second catalytic resistor, wherein the first catalytic resistor and the second catalytic resistor are respectively arranged on two opposite bridge arms, and the resistance value of the first catalytic resistor is equal to the resistance value of the second catalytic resistor; the reference component comprises a first reference resistor and a second reference resistor, the first reference resistor and the second reference resistor are respectively arranged on the other two bridge arms, and the resistance value of the first reference resistor is equal to the resistance value of the second reference resistor; the first reference resistor and the second reference resistor are prepared by doping polysilicon so that the resistance values thereof decrease with the increase of temperature. According to the invention, on the premise of setting two diagonally arranged catalytic resistors and improving the sensitivity of the hydrogen sensor, the sensitivity of the whole hydrogen sensor is further improved by using the polysilicon doped resistor as a reference resistor.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a hydrogen sensor and a preparation method thereof.
Background
Hydrogen fuel cells have been widely used in the fields of automobiles, nuclear power, etc., and in order to avoid explosion caused by hydrogen leakage, measurement of hydrogen leakage in the links of hydrogen preparation, transportation, storage and utilization is a problem that needs to be focused and solved. In a plurality of principles for detecting hydrogen leakage, the MEMS catalytic combustion type hydrogen sensor has wide development prospect due to the characteristics of high sensitivity, small volume, low cost and the like.
The MEMS catalytic combustion type hydrogen sensor converts the hydrogen concentration change into a voltage output change. To achieve high sensitivity, high linearity and temperature compensation of the device, designers typically prepare a wheatstone bridge consisting of four resistors A, B, C and D. Referring to FIG. 1, the resistances of the resistors are equal and are denoted as R 1 A is the catalytic resistance and B, C and D are the reference resistances. In preparation, the oxide layer covered on the surface of the catalytic resistor is removed so that the oxide layer is exposed to air to catalyze the combustion of hydrogen. Ginseng radixThe surface of the test resistor is still covered with an oxide layer and does not react with hydrogen, so that errors caused by environmental changes can be eliminated, and temperature compensation is realized. The resistor is typically made of platinum, palladium or other positive temperature coefficient of resistance metal that is sensitive to hydrogen so that the resistance value can become greater as the temperature increases.
Taking platinum as an example, when the power supply voltage is U, the electromagnetic heat raises the temperature of the four resistors to the required range, the temperature is about 300-350 ℃, the resistance of the resistor is increased and tends to be stable, and the resistance of each resistor is R 0 . When hydrogen passes through, the catalytic resistor A catalyzes the hydrogen to burn, the temperature of the catalytic resistor is further increased by the heat of burning, and the resistance value of the catalytic resistor A is recorded as R 0 +ΔR 1 While the resistance of the rest of the reference resistors is unchanged. The balance of the wheatstone bridge is destroyed, thereby producing a voltage output V 1 The method comprises the following steps:
。
the hydrogen sensor sensitivity is smaller when there is only one catalytic resistance. In order to improve the sensitivity, there is a prior art technique in which two catalytic resistors are provided diagonally, and the sensitivity of the hydrogen sensor is twice that of a hydrogen sensor provided with only one catalytic resistor. For example, after setting resistors A and D as catalytic resistors, voltage output V 2 The method comprises the following steps:
。
however, the sensitivity of the hydrogen sensor is improved to a limited extent, and thus the requirement of people for high sensitivity cannot be met.
Disclosure of Invention
Therefore, the invention aims to solve the technical problem that the sensitivity of the existing hydrogen sensor cannot meet the requirement, and provides the hydrogen sensor and the processing method thereof, wherein the polysilicon doped resistor is used as a reference resistor, so that the sensitivity of the hydrogen sensor is improved.
The invention provides a hydrogen sensor, which comprises a Wheatstone bridge, wherein the Wheatstone bridge comprises four bridge arms and a catalytic assembly, the catalytic assembly comprises a first catalytic resistor and a second catalytic resistor, the first catalytic resistor and the second catalytic resistor are respectively arranged on two opposite bridge arms, and the resistance value of the first catalytic resistor is equal to the resistance value of the second catalytic resistor; the reference component comprises a first reference resistor and a second reference resistor, the first reference resistor and the second reference resistor are respectively arranged on the rest two bridge arms, and the resistance value of the first reference resistor is equal to the resistance value of the second reference resistor; the first reference resistor and the second reference resistor are prepared by doping polysilicon, so that the resistance values of the first reference resistor and the second reference resistor are reduced along with the increase of temperature.
In one embodiment of the present invention, the first catalytic resistor, the second catalytic resistor, the first reference resistor and the second reference resistor each include a connection portion and a bending portion, the bending portion is configured as a serpentine bending structure, the connection portions are disposed at two ends of the bending portion, and the connection portions are used for connecting with electrodes.
In one embodiment of the present invention, the first catalytic resistor is disposed on one side of the first reference resistor, and the connection portion of the first catalytic resistor corresponds to the connection portion of the first reference resistor, and the bending portion of the first catalytic resistor corresponds to the bending portion of the first reference resistor; the second catalytic resistor is arranged on one side of the second reference resistor, the connecting part of the second catalytic resistor corresponds to the connecting part of the second reference resistor, and the bending part of the second catalytic resistor corresponds to the bending part of the second reference resistor.
In one embodiment of the present invention, the bending portions of the first catalytic resistor and the second catalytic resistor each include a plurality of first bending concave portions and a plurality of first bending convex portions, and the plurality of first bending concave portions and the plurality of first bending convex portions are alternately arranged in sequence; the bending parts of the first reference resistor and the second reference resistor comprise a plurality of second bending concave parts and a plurality of second bending convex parts, and the second bending concave parts and the second bending convex parts are sequentially and alternately arranged; wherein the first bending convex part of the first catalytic resistor extends into the second bending concave part of the first reference resistor, and the second bending convex part of the first reference resistor extends into the first bending concave part of the first catalytic resistor; the first bending convex part of the second catalytic resistor stretches into the second bending concave part of the second reference resistor, and the second bending convex part of the second reference resistor stretches into the first bending concave part of the second catalytic resistor.
In one embodiment of the present invention, when the power is not applied and the hydrogen is not applied, the resistance of the first catalytic resistor and the resistance of the second catalytic resistor are both R 1 The resistance of the first reference resistor and the resistance of the second reference resistor are R 2 The method comprises the steps of carrying out a first treatment on the surface of the Under the condition of power on and no hydrogen on, the value of the power supply voltage is U, and the resistance values of the resistors are equal and recorded as R 0 The method comprises the steps of carrying out a first treatment on the surface of the Under the condition of energizing and energizing hydrogen, the resistance value of the first catalytic resistor and the resistance value of the second catalytic resistor are recorded as R 0 +ΔR 1 The resistance of the first reference resistor and the resistance of the second reference resistor are R 0 -ΔR 2 The method comprises the steps of carrying out a first treatment on the surface of the Voltage output V at this time out The method comprises the following steps:
；
wherein the performance parameter is selected to satisfy ΔR 2 =ΔR 1 Such that the sensitivity is at a maximum.
In one embodiment of the invention, the semiconductor device further comprises a silicon substrate, wherein the silicon substrate comprises a first plane and a second plane which are oppositely arranged, a heat insulation groove is formed in the first plane, and the heat insulation groove penetrates to the second plane; a first film layer disposed above the first plane, the first film layer including an insulating region corresponding to the insulating slot; the catalytic assembly and the reference assembly are arranged above the first film layer, and the first catalytic resistor, the second catalytic resistor, the first reference resistor and the second reference resistor are arranged in the adiabatic region; a second membrane layer, the second membrane layer being disposed over the catalytic assembly and the reference assembly; wherein the first catalytic resistor and the second catalytic resistor are at least partially exposed to react with hydrogen.
In one embodiment of the invention, a vent chamber is provided on the second plane, the vent chamber being in communication with the thermally insulated tank.
In one embodiment of the present invention, the first film layer is a composite film layer, and the first film layer includes at least one silicon oxide film layer and at least one silicon nitride film layer.
In one embodiment of the present invention, the second film layer includes at least one silicon oxide film layer.
The invention also provides a preparation method for preparing the hydrogen sensor, which comprises the following steps:
s1, depositing a first film layer above a first plane of a silicon substrate;
s2, depositing polysilicon above the first film layer;
s3, forming a doped resistor connection region on the polysilicon;
s4, forming a first reference resistor and a second reference resistor on the polysilicon;
s5, removing the polysilicon outside the doped resistor connecting region, the first reference resistor and the second reference resistor;
s6, preparing catalytic resistors, leads and electrodes above the first film layer;
s7, depositing a second film layer above the first film layer;
s8, etching the second film layer to expose the first catalytic resistor, the second catalytic resistor, the electrode and part of the doped resistor connecting area;
s9, preparing a bonding pad, wherein the bonding pad is connected with the electrode;
s10, etching a ventilation cavity on a second plane of the silicon substrate;
and S11, etching an insulation groove on the ventilation cavity to obtain the hydrogen sensor.
Compared with the prior art, the technical scheme of the invention has the following advantages:
according to the hydrogen sensor disclosed by the invention, the polysilicon doping resistor is used as the reference resistor, so that when the polysilicon doping concentration is in a certain range, the temperature coefficient of the resistor is negative, namely the resistance value of the resistor can be reduced along with the increase of the temperature. On the premise of setting two first catalytic resistors and two second catalytic resistors which are diagonally arranged and improving the sensitivity of the hydrogen sensor, the sensitivity of the whole hydrogen sensor is further improved.
Drawings
In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings, in which,
FIG. 1 is a schematic diagram of a prior art Wheatstone bridge;
FIG. 2 is a schematic diagram of a Wheatstone bridge without power and hydrogen in accordance with a preferred embodiment of the present invention;
FIG. 3 is a schematic top view of a first catalytic resistor and a first reference resistor according to a preferred embodiment of the present invention;
FIG. 4 is a schematic top view of a first catalytic resistor according to a preferred embodiment of the present invention;
FIG. 5 is a schematic top view of a first reference resistor according to a preferred embodiment of the present invention;
FIG. 6 is a schematic top view of a hydrogen sensor according to a preferred embodiment of the present invention;
FIG. 7 is a schematic diagram of a Wheatstone bridge with and without hydrogen being applied in a preferred embodiment of the invention;
FIG. 8 is a schematic diagram of a Wheatstone bridge with hydrogen energized in accordance with a preferred embodiment of the present invention;
fig. 9 is a schematic front view of a hydrogen sensor according to a preferred embodiment of the present invention.
Description of the specification reference numerals: 11. a first catalytic resistor; 12. a second catalytic resistor; 13. a first reference resistor; 14. a second reference resistor; 151. a connection part; 152. a bending part; 1521. a first bending concave portion; 1522. a first bending convex part; 1523. a second bending concave portion; 1524. a second bending convex part; 16. an electrode; 17. a bonding pad; 18. a lead wire; 19. doping the resistor connection region; 20. a silicon substrate; 21. a heat insulation groove; 22. a ventilation chamber; 31. a first film layer; 311. a silicon oxide film layer; 312. a silicon nitride film layer; 32. and a second film layer.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and specific examples, which are not intended to be limiting, so that those skilled in the art will better understand the invention and practice it.
Referring to FIG. 2, the present invention discloses a hydrogen sensor comprising a Wheatstone bridge comprising four legs, a catalytic assembly and a reference assembly. The catalytic assembly comprises a first catalytic resistor 11 and a second catalytic resistor 12, the catalytic resistors being adapted to contact the combustion of hydrogen. The resistance of the first catalytic resistor 11 is equal to the resistance of the second catalytic resistor 12, and the first catalytic resistor 11 and the second catalytic resistor 12 are respectively arranged on two opposite bridge arms. The reference assembly comprises a first reference resistor 13 and a second reference resistor 14, and the reference resistors are not reacted with hydrogen and are used for eliminating errors caused by environmental changes and realizing temperature compensation. The resistance of the first reference resistor 13 is equal to that of the second reference resistor 14, and the first reference resistor 13 and the second reference resistor 14 are respectively arranged on the other two bridge arms. The first reference resistor 13 and the second reference resistor 14 are prepared by doping polysilicon so that the resistance value thereof is reduced with the increase of temperature.
According to the hydrogen sensor disclosed by the invention, the polysilicon doping resistor is used as the reference resistor, so that when the polysilicon doping concentration is in a certain range, the temperature coefficient of the resistor is negative, namely the resistance value of the resistor can be reduced along with the increase of the temperature. On the premise of arranging two first catalytic resistors 11 and two second catalytic resistors 12 which are diagonally arranged and improving the sensitivity of the hydrogen sensor, the sensitivity of the whole hydrogen sensor is further improved.
Referring to fig. 3 and 6, in some embodiments of the hydrogen sensor according to the present invention, the first catalytic resistor 11, the second catalytic resistor 12, the first reference resistor 13, and the second reference resistor 14 each include a connection portion 151 and a bending portion 152, the bending portion 152 is configured in a serpentine bent structure, the connection portions 151 are disposed at both ends of the bending portion 152, and the connection portions 151 are used for connection with the electrodes 16. Each resistor is arranged to be of a serpentine bent structure, heat dissipation can be guaranteed, and failure of the sensor due to thermal expansion is avoided. According to different requirements, different sizes, bending times and the like can be selected.
Further, referring to fig. 3 and 6, in some embodiments of the hydrogen sensor according to the present invention, the first catalytic resistor 11 is disposed on one side of the first reference resistor 13, and the connection portion 151 of the first catalytic resistor 11 corresponds to the connection portion 151 of the first reference resistor 13, and the bending portion 152 of the first catalytic resistor 11 corresponds to the bending portion 152 of the first reference resistor 13; the second catalytic resistor 12 is disposed on one side of the second reference resistor 14, and the connection portion 151 of the second catalytic resistor 12 corresponds to the connection portion 151 of the second reference resistor 14, and the bending portion 152 of the second catalytic resistor 12 corresponds to the bending portion 152 of the second reference resistor 14. On the basis of setting up to snakelike kink form structure, set up catalytic resistor near reference resistance, under the condition of circular telegram and hydrogen, catalytic resistor's temperature can transmit for reference resistance, and because first reference resistance 13 and second reference resistance 14 all adopt polycrystalline silicon to carry out the doping preparation, the resistance can reduce along with the rising of temperature, consequently the sensitivity of sensor can further obtain improving. In addition, in the case of this structure, the size of the sensor can be reduced.
Referring to fig. 4, 5 and 6, in some embodiments of the hydrogen sensor according to the present invention, the bent portions 152 of the first catalytic resistor 11 and the second catalytic resistor 12 each include a plurality of first bending concave portions 1521 and a plurality of first bending convex portions 1522, and the plurality of first bending concave portions 1521 and the plurality of first bending convex portions 1522 are sequentially and alternately arranged.
The bending portions 152 of the first reference resistor 13 and the second reference resistor 14 each include a plurality of second bending concave portions 1523 and a plurality of second bending convex portions 1524, and the plurality of second bending concave portions 1523 and the plurality of second bending convex portions 1524 are alternately arranged in order.
Wherein, the first bending convex portion 1522 of the first catalytic resistor 11 extends into the second bending concave portion 1523 of the first reference resistor 13, and the second bending convex portion 1524 of the first reference resistor 13 extends into the first bending concave portion 1521 of the first catalytic resistor 11; the first bending protrusion 1522 of the second catalytic resistor 12 protrudes into the second bending recess 1523 of the second reference resistor 14, and the second bending protrusion 1524 of the second reference resistor 14 protrudes into the first bending recess 1521 of the second catalytic resistor 12.
By means of the structure, on one hand, the first reference resistor 13 and the second reference resistor 14 which are prepared by doping polysilicon are matched, so that the sensitivity of the sensor can be further improved; on the other hand, the four resistors of the structure occupy only the positions of the original two resistors, and compared with the hydrogen sensor which is provided with the resistors in a scattered manner and occupies the four positions, the chip size is halved, so that the structure has the advantages in the aspects of expanding the application field and reducing the process cost.
In the prior art, there are resistors comprising bending concave parts and bending convex parts, however, the resistors are generally distributed and not wound, and therefore occupy four positions. This is because each resistor of the prior art is made of a metal material and needs to be dispersed to dissipate heat. If the distance is set closer, the resistance of each of the four resistors increases with temperature transfer, resulting in reduced sensitivity of the sensor. In addition, failure due to thermal expansion may also occur.
Referring to FIG. 2, in some embodiments, in the hydrogen sensor according to the present invention, when the power is not applied and the hydrogen is not applied, the resistance of the first catalytic resistor 11 and the resistance of the second catalytic resistor 12 are both R 1 The resistance of the first reference resistor 13 and the resistance of the second reference resistor 14 are R 2 . Can catalyze the reaction under the condition of no power and no hydrogen according to the actual requirementsResistance R of resistor 1 And the resistance value R of the reference resistor 2 Any arrangement is made as long as the resistance values of the resistors are equal to R under the condition that the electricity is supplied and the hydrogen is not supplied 0 Can be used for how to set R 1 、R 2 To ensure that the resistance values of the resistors are equal to R under the condition of being electrified and not electrified with hydrogen 0 And will not be described in detail as being common general knowledge to a person skilled in the art.
Referring to FIG. 7, when the power is applied and hydrogen is not applied, the supply voltage has a value of U, and the resistances of the resistors are equal and R 0 . Specifically, in this case, the electromagnetic heat causes the four resistances to rise in temperature, at which time the resistance of the first catalytic resistor 11 and the resistance of the second catalytic resistor 12 increase, and the resistance of the first reference resistor 13 and the resistance of the second reference resistor 14 decrease, and the resistances of the four resistances after heat balance are equal.
Referring to fig. 8, when the power is applied and the hydrogen is applied, the resistance of the first catalytic resistor 11 and the resistance of the second catalytic resistor 12 are both R 0 +ΔR 1 The resistance of the first reference resistor 13 and the resistance of the second reference resistor 14 are R 0 -ΔR 2 . Specifically, after hydrogen is introduced, the catalytic resistor is further heated up by combustion, so that the resistance value of the catalytic resistor is further increased. Meanwhile, due to the fact that the first reference resistor 13, the first catalytic resistor 11, the second reference resistor 14 and the second catalytic resistor 12 are in a serpentine winding structure, high temperature of the corresponding catalytic resistor can be transferred to the reference resistor with relatively low temperature, and accordingly the temperature of the corresponding reference resistor is increased, and the resistance is further reduced.
Voltage output V at this time out The method comprises the following steps:
。
wherein the performance parameter is selected to satisfy ΔR 2 =ΔR 1 To maximize sensitivity.
The maximum value is as follows:
。
comparing this value with the voltage output value in the prior art, it can be seen that in this case, the sensitivity of the hydrogen sensor according to the present invention is twice or more that of the hydrogen sensor using two catalytic resistors in the prior art.
Since the structures of the resistors, the electrodes 16, and the like are axisymmetric, only half of the structures are drawn in fig. 9 to simplify the pattern and facilitate recognition. Referring to fig. 9, the hydrogen sensor of the present invention, in some embodiments, further includes a silicon substrate 20, a first film 31, and a second film 32. The silicon substrate 20 includes a first plane and a second plane which are disposed opposite to each other, and the first plane is provided with a heat insulating groove 21, and the heat insulating groove 21 penetrates to the second plane. The first film 31 is disposed above the first plane, the first film 31 including an insulating region corresponding to the insulating slot 21. The catalytic assembly and the reference assembly are all disposed above the first membrane layer 31, and the first catalytic resistor 11, the second catalytic resistor 12, the first reference resistor 13 and the second reference resistor 14 are all disposed within the adiabatic region. A second membrane layer 32 is disposed overlying the catalytic assembly and the reference assembly; wherein the first catalytic resistor 11 and the second catalytic resistor 12 are at least partially exposed to react with hydrogen. The heat insulating tank 21 is configured to cooperate with the first film 31, so that heat generated by each resistor can be prevented from being conducted through the silicon substrate 20, and the temperature can be maintained for catalytic combustion with hydrogen.
The number of layers, materials, thicknesses, and the like of the first film layer 31 and the second film layer 32 can be adjusted by selecting different first film layers and second film layers according to different requirements. Preferably, since the hydrogen sensor belongs to a thermal device, the situation of thermal mismatch is avoided, and the sum of layers is preferably three-layer or five-layer structure.
Further, referring to fig. 9, in some embodiments, the hydrogen sensor of the present invention is provided with a ventilation chamber 22 on the second plane, and the ventilation chamber 22 communicates with the heat insulation groove 21. The ventilation cavity 22 is used for circulating gas in the heat insulation groove 21, so that the air in the heat insulation groove 21 is prevented from damaging the upper film layer and causing device failure under the action of thermal expansion, and the quality of the sensor is ensured. Different sizes of ventilation lumens 22 can be selected according to different needs.
Further, referring to fig. 9, in some embodiments of the hydrogen sensor according to the present invention, the first film 31 is a composite film, and the first film 31 includes at least one silicon oxide film 311 and at least one silicon nitride film 312 to achieve thermal insulation; the second film 32 includes at least one silicon oxide film to prevent the reference resistances from reacting with hydrogen.
The invention discloses a preparation method of a hydrogen sensor, which is used for preparing the hydrogen sensor in the embodiment. Specifically, the preparation method comprises the following steps.
S1, depositing a first film 31 over a first plane of the silicon substrate 20. Preferably, a dense silicon oxide film 311 is deposited on the silicon substrate 20, first by thermal oxidation, to a thickness of 30nm-1500nm. And a silicon nitride film 312 with prestress is deposited on the silicon oxide film 311 by a plasma enhanced vapor deposition method, and the thickness is 30nm-1000nm.
And S2, depositing polysilicon above the first film layer 31. Preferably, polysilicon is deposited over the silicon nitride film 312 to a thickness of 300nm to 800nm based on a low pressure chemical vapor deposition process.
And S3, forming a doped resistor connection region 19 on the polysilicon. Preferably, the doped resistive connection area 19 is formed on the polysilicon based on an ion implantation or diffusion process. The doped resistor connecting region 19 is a conventional technical means, so that the subsequent bonding pad 17 can be stably and electrically connected with the first reference resistor 13 and the second reference resistor 14.
And S4, forming a first reference resistor 13 and a second reference resistor 14 on the polycrystalline silicon. Preferably, the first reference resistor 13 and the second reference resistor 14 are formed by doping on the polysilicon based on an ion implantation or diffusion process.
S5, removing the polysilicon outside the doped resistor connecting region 19, the first reference resistor 13 and the second reference resistor 14.
S6, preparing each catalytic resistor, the lead 18 and the electrode 16 above the first film 31. Preferably, the first catalytic resistor 11, the second catalytic resistor 12, the platinum lead 18 and the platinum electrode 16 are prepared based on a sputtering and stripping method, and the thickness is 100nm-300nm. The material of the lead 18, the electrode 16, and the like may be selected according to actual requirements, and may be conductive, for example, platinum, aluminum, gold, doped monocrystalline silicon, doped polycrystalline silicon, and the like. Preferably, the lead 18, the electrode 16 and the catalytic resistor are all made of the same material, so that the electrode 16, the lead 18 and the catalytic resistor are manufactured at one time, and the cost is saved.
And S7, depositing a second film layer 32 above the first film layer 31. Preferably, a silicon oxide film layer having a prestress is formed to cover each resistor, electrode 16, lead 18, etc. based on plasma enhanced vapor deposition, with a thickness of 30nm to 1000nm.
And S8, etching the second film layer 32 to expose the first catalytic resistor 11, the second catalytic resistor 12, the electrode 16 and part of the doped resistor connecting region 19. By exposing each catalytic resistor, the reaction with hydrogen is facilitated; subsequent fabrication of the bond pad 17 is facilitated by exposing each electrode 16 and a portion of the doped resistor connection region 19.
And S9, preparing a bonding pad 17, wherein the bonding pad 17 is connected with the electrode 16. Preferably, the gold pad 17 is prepared based on a sputtering and stripping method, and has a thickness of 100nm-300nm. The material of the pad 17 may be selected according to actual requirements, and may be a metal that is easy to bond wires and does not react with hydrogen, such as aluminum or gold.
And S10, etching the ventilation cavity 22 on the second plane of the silicon substrate 20. Preferably, the venting chamber 22 is etched based on a dry etching process.
And S11, etching a heat insulation groove 21 on the ventilation cavity 22 to obtain the hydrogen sensor. Preferably, the adiabatic slots 21 are etched based on a dry etching process.
The thickness to be matched is also different depending on different factors, such as the power supply voltage, the resistance value, the size of the heat insulation groove 21, and the like, and can be selected according to actual requirements.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.
Claims (7)
1. A hydrogen sensor comprising a wheatstone bridge, the wheatstone bridge comprising four legs, and:
the catalytic assembly comprises a first catalytic resistor and a second catalytic resistor, the first catalytic resistor and the second catalytic resistor are respectively arranged on two opposite bridge arms, and the resistance value of the first catalytic resistor is equal to the resistance value of the second catalytic resistor;
the reference component comprises a first reference resistor and a second reference resistor, the first reference resistor and the second reference resistor are respectively arranged on the rest two bridge arms, and the resistance value of the first reference resistor is equal to the resistance value of the second reference resistor;
the first reference resistor and the second reference resistor are prepared by doping polysilicon, so that the resistance values of the first reference resistor and the second reference resistor are reduced along with the increase of temperature;
the first catalytic resistor, the second catalytic resistor, the first reference resistor and the second reference resistor all comprise connecting parts and bending parts, the bending parts are arranged into a serpentine bending structure, the connecting parts are arranged at two ends of the bending parts, and the connecting parts are used for being connected with electrodes;
the first catalytic resistor is arranged on one side of the first reference resistor, the connecting part of the first catalytic resistor corresponds to the connecting part of the first reference resistor, and the bending part of the first catalytic resistor corresponds to the bending part of the first reference resistor; the second catalytic resistor is arranged on one side of the second reference resistor, the connecting part of the second catalytic resistor corresponds to the connecting part of the second reference resistor, and the bending part of the second catalytic resistor corresponds to the bending part of the second reference resistor;
the bending parts of the first catalytic resistor and the second catalytic resistor comprise a plurality of first bending concave parts and a plurality of first bending convex parts, and the first bending concave parts and the first bending convex parts are sequentially and alternately arranged; the bending parts of the first reference resistor and the second reference resistor comprise a plurality of second bending concave parts and a plurality of second bending convex parts, and the second bending concave parts and the second bending convex parts are sequentially and alternately arranged;
wherein the first bending convex part of the first catalytic resistor extends into the second bending concave part of the first reference resistor, and the second bending convex part of the first reference resistor extends into the first bending concave part of the first catalytic resistor; the first bending convex part of the second catalytic resistor stretches into the second bending concave part of the second reference resistor, and the second bending convex part of the second reference resistor stretches into the first bending concave part of the second catalytic resistor.
2. The hydrogen sensor of claim 1, wherein:
under the condition of no power-on and no hydrogen power-on, the resistance value of the first catalytic resistor and the resistance value of the second catalytic resistor are recorded as R 1 The resistance of the first reference resistor and the resistance of the second reference resistor are R 2 ；
Under the condition of power on and no hydrogen on, the value of the power supply voltage is U, and the resistance values of the resistors are equal and recorded as R 0 ；
Under the condition of energizing and energizing hydrogen, the resistance value of the first catalytic resistor and the resistance value of the second catalytic resistor are recorded as R 0 +ΔR 1 The resistance of the first reference resistor and the resistance of the second reference resistor are R 0 -ΔR 2 The method comprises the steps of carrying out a first treatment on the surface of the Voltage output V at this time out The method comprises the following steps:
；
wherein the performance parameter is selected to satisfy ΔR 2 =ΔR 1 Such that the sensitivity is at a maximum.
3. The hydrogen sensor according to claim 1 or 2, characterized by further comprising:
the silicon substrate comprises a first plane and a second plane which are oppositely arranged, wherein a heat insulation groove is formed in the first plane, and the heat insulation groove penetrates through the second plane;
a first film layer disposed above the first plane, the first film layer including an insulating region corresponding to the insulating slot; the catalytic assembly and the reference assembly are arranged above the first film layer, and the first catalytic resistor, the second catalytic resistor, the first reference resistor and the second reference resistor are arranged in the adiabatic region;
a second membrane layer, the second membrane layer being disposed over the catalytic assembly and the reference assembly;
wherein the first catalytic resistor and the second catalytic resistor are at least partially exposed to react with hydrogen.
4. A hydrogen sensor according to claim 3, wherein: and the second plane is provided with a ventilation cavity which is communicated with the heat insulation groove.
5. A hydrogen sensor according to claim 3, wherein: the first film layer is a composite film layer and comprises at least one silicon oxide film layer and at least one silicon nitride film layer.
6. A hydrogen sensor according to claim 3, wherein: the second film layer comprises at least one silicon oxide film layer.
7. A method of producing the hydrogen sensor according to any one of claims 1 to 6, comprising the steps of:
s1, depositing a first film layer above a first plane of a silicon substrate;
s2, depositing polysilicon above the first film layer;
s3, forming a doped resistor connection region on the polysilicon;
s4, forming a first reference resistor and a second reference resistor on the polysilicon;
s5, removing the polysilicon outside the doped resistor connecting region, the first reference resistor and the second reference resistor;
s6, preparing catalytic resistors, leads and electrodes above the first film layer;
s7, depositing a second film layer above the first film layer;
s8, etching the second film layer to expose the first catalytic resistor, the second catalytic resistor, the electrode and part of the doped resistor connecting area;
s9, preparing a bonding pad, wherein the bonding pad is connected with the electrode;
s10, etching a ventilation cavity on a second plane of the silicon substrate;
and S11, etching an insulation groove on the ventilation cavity to obtain the hydrogen sensor.
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| CN115308270A (en) * | 2022-08-05 | 2022-11-08 | 郑州炜盛电子科技有限公司 | Palladium alloy film hydrogen sensor and preparation method and use method thereof |
| CN218629628U (en) * | 2022-11-17 | 2023-03-14 | 四川拓景科技有限公司 | Palladium alloy hydrogen sensor |
| CN116858895A (en) * | 2023-06-27 | 2023-10-10 | 苏州亿波达光电子科技有限公司 | Hydrogen sensor with small volume and processing method thereof |
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| US4622856A (en) * | 1983-05-30 | 1986-11-18 | Siemens Aktiengesellschaft | Sensor with polycrystalline silicon resistors |
| JPH116810A (en) * | 1997-06-18 | 1999-01-12 | Yazaki Corp | Gas sensor and contact combustion gas sensor as well as manufacture |
| CN104677952A (en) * | 2015-03-25 | 2015-06-03 | 海卓赛思（苏州）传感技术有限公司 | High-stability film hydrogen sensor and use method thereof |
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