WO2022145291A1 - Multilayer film structure, method for manufacturing multilayer film structure, and electronic element - Google Patents

Multilayer film structure, method for manufacturing multilayer film structure, and electronic element Download PDF

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WO2022145291A1
WO2022145291A1 PCT/JP2021/047360 JP2021047360W WO2022145291A1 WO 2022145291 A1 WO2022145291 A1 WO 2022145291A1 JP 2021047360 W JP2021047360 W JP 2021047360W WO 2022145291 A1 WO2022145291 A1 WO 2022145291A1
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layer
insulating layer
multilayer film
film structure
adsorption
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French (fr)
Japanese (ja)
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誠 嘉数
敏之 大石
聖祐 金
浩司 小山
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国立大学法人佐賀大学
アダマンド並木精密宝石株式会社
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Publication of WO2022145291A1 publication Critical patent/WO2022145291A1/en

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40—Oxides
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02—Epitaxial-layer growth
    • C30B25/18—Epitaxial-layer growth characterised by the substrate
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/16—Oxides
    • C30B29/20—Aluminium oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409—Unipolar field-effect transistors
    • H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H01L29/786—Thin film transistors, i.e. transistors with a channel being at least partly a thin film

Definitions

  • the present invention relates to a multilayer film structure.
  • the present invention also relates to a method for manufacturing a multilayer film structure. Further, the present invention relates to an electronic device having a multilayer film structure.
  • Diamond semiconductors have a bandgap of 5.47 electron volts, which is about five times that of silicon semiconductors, and have an insulation withstand voltage of 10 MV / cm or more, which is 33 times or more the value of 0.3 MV / cm of silicon, so they are highly efficient. It is expected as a semiconductor material for high power and high frequency transistors. In addition to diamond, other materials with a large bandgap have been proposed.
  • the present inventors have obtained a hole surface concentration of 1 x 10 14 cm -2 by providing a nitrogen dioxide (NO 2 ) adsorption layer on the surface of a hydrogen-adsorbed diamond crystal. Further, the mobility of the field effect transistor (FET) is 32 cm 2 / Vs. However, this mobility is significantly lower than the original mobility of diamond (electrons 4500 cm 2 / Vs, holes 3800 cm 2 / Vs). As described above, even a semiconductor having a large bandgap and expected to have higher mobility due to its dielectric strength and the like cannot express the original properties of the semiconductor material.
  • NO 2 nitrogen dioxide
  • Non-Patent Document 1 Kazu reports that NO 2 molecule becomes an acceptor impurity for hydrogen-terminated diamond and forms holes.
  • the electrical conduction of the whole carrier in the gate structure of the FET will be described with reference to FIGS. 4 and 5.
  • this multilayer film structure 20 201
  • a diamond crystal 1 is used as a substrate, and a hydrogen adsorption layer 12 is provided on the surface thereof, a NO 2 adsorption layer 3 is formed therein, an Al 2 O 3 layer 4 is deposited, and finally.
  • the gate metal layer 5 was deposited on the surface.
  • Non-Patent Documents 2 and 3 also disclose transistors using diamond.
  • Patent Document 1 describes a diamond substrate, a surface layer formed by terminating the surface of the diamond substrate with hydrogen atoms, and an atmosphere formed on the surface layer by exposing the surface layer to the atmosphere.
  • the first adsorption layer made of the above-mentioned molecules, the source electrode and the drain electrode formed on the first adsorption layer at a distance from each other, and the first exposed between the source electrode and the drain electrode.
  • Non-Patent Document 1 methods for expressing the original mobility of a substrate material such as a diamond element are being studied.
  • the NO 2 molecule acceptor that generated the hole becomes a negatively charged ionization acceptor, so the hole running in the hydrogen adsorption layer and the NO 2 adsorption layer between the diamond crystal layer and the Al 2 O 3 film is Due to the ionization impurity scattering mechanism by the NO 2 molecule ionization acceptor and the surface scattering mechanism due to the inevitable surface roughness on the diamond surface, the mobility is significantly lower than the original mobility of diamond, 3800 cm 2 / Vs. Can not. As a result, the channel resistance was also high, and it was not possible to show the original physical characteristics of diamond.
  • an object of the present invention is to provide a multilayer film structure having improved mobility, a method for manufacturing the same, and the like.
  • the present inventor has found that the following invention meets the above object, and has reached the present invention. That is, the present invention relates to the following invention.
  • a multilayer film structure having a second insulating layer and a gate electrode layer arranged on the second insulating layer.
  • the substrate layer contains any crystal selected from the group consisting of gallium nitride (GaN), silicon carbide (SiC), gallium oxide (Ga 2 O 3 ), and diamond, and the first insulation.
  • the substrate layer is a layer of diamond crystals having a hydrogen adsorption layer
  • the first insulating layer is a layer of aluminum oxide (Al 2 O 3 ) having a thickness of 4 to 12 nm, and the adsorption layer is.
  • the nitrogen dioxide (NO 2 ) adsorption layer, the second insulating layer is a layer of aluminum oxide (Al 2 O 3 ) having a thickness of 4 to 100 nm, and the gate electrode is a metal layer.
  • ⁇ 4> An electronic device including the multilayer film structure according to any one of ⁇ 1> to ⁇ 3>.
  • a controlled atmosphere any one selected from the group consisting of nitrogen dioxide (NO 2 ), nitrogen monoxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ). It has a forming step of contacting gas molecules to form an adsorption layer, and a second deposition step of depositing a member forming a second insulating layer on the surface of the adsorption layer under a controlled atmosphere.
  • the production according to ⁇ 5> which comprises a hydrogen adsorption layer forming step of irradiating the surface of the substrate layer with hydrogen plasma to form a hydrogen adsorption layer before the first deposition step.
  • Method. ⁇ 7> The hydrogen adsorption forming step, the first deposition step, the forming step, and the second deposition step are performed in the same treatment tank, and the atmosphere is a vacuum or nitrogen-substituted atmosphere.
  • the first deposition step is for depositing aluminum oxide (Al 2 O 3 ), the sample temperature is 50 to 300 ° C., and the forming step is nitrogen dioxide (NO 2 ).
  • the concentration of NO 2 gas is 0.2% or more
  • the supply time is 3 to 20 minutes
  • the degree of vacuum is 6.67 kPa to 26.7 kPa in the forming step.
  • the sample temperature is 50 to 200 ° C.
  • the second deposition step is to deposit aluminum oxide (Al 2 O 3 ), and the sample temperature is 50 to 200 ° C.
  • a multilayer film structure having improved mobility, a method for manufacturing the same, and the like are provided.
  • the multilayer film structure of the present invention has a substrate layer having a band gap of 3.0 electron volt or more, a first insulating layer arranged on the substrate layer, and an arrangement on the first insulating layer.
  • a member forming a first insulating layer is deposited on the surface of a substrate layer having a band gap of 3.0 electron volt or more under a controlled atmosphere. From nitrogen dioxide (NO 2 ), nitrogen monoxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ) in a controlled atmosphere on the surface of the first insulating layer.
  • the multilayer film structure of the present invention can exhibit excellent mobility close to the original mobility of the substrate layer.
  • the method for producing a multilayer film structure of the present invention the multilayer film structure of the present invention can be produced, and the configurations corresponding to each can be mutually used in the present application.
  • the present invention is negative from the hole traveling layer by providing a new aluminum oxide (Al 2 O 3 ) layer between the layer on which the hole travels and the layer of the nitrogen dioxide (NO 2 ) molecule acceptor that produces the hole.
  • Al 2 O 3 aluminum oxide
  • NO 2 nitrogen dioxide
  • the mobility of a conventional diamond substrate in a transistor of 30 cm 2 / Vs can be increased 100 times or more to the original mobility of diamond of 3800 cm 2 / Vs.
  • the sheet resistance can be reduced to 1/100 or less.
  • the current value can be increased 100 times or more.
  • the competent power which is the power that can be controlled by the transistor, can be increased 100 times or more.
  • FIG. 1 is a schematic view of the multilayer film structure 10 according to the first embodiment of the present invention.
  • the multilayer film structure 10 has a substrate layer 1, a first insulating layer 2, an adsorption layer 3, a second insulating layer 4, and a gate electrode 5 in this order from the bottom when the substrate is viewed as the lowest layer. ..
  • This multilayer film structure 10 is used for various electronic devices.
  • FIG. 2 is a schematic view of the multilayer film structure 101 according to the second embodiment of the present invention.
  • the multilayer film structure 101 conforms to the structure of the multilayer film structure 10, and has a structure in which the surface of the substrate 1 is subjected to hydrogen adsorption treatment to provide the hydrogen adsorption layer 12.
  • the multilayer film structure 10 (101) has a substrate layer 1.
  • the substrate layer 1 has a bandgap of 3.0 electron volts or more.
  • Such a substrate having a large bandgap has not been able to exhibit the mobility expected from the bandgap or the like in the conventional multilayer film structure.
  • it by using it as the substrate layer of the multilayer film structure 10 (101) of the present invention, its excellent mobility can be exhibited.
  • the substrate layer 1 can include any crystal selected from the group consisting of gallium nitride (GaN), silicon carbide (SiC), gallium oxide (Ga 2 O 3 ), and diamond. This crystal may be substantially any one, or a combination of the above-mentioned crystals or a combination of these and other crystals may be used.
  • the bandgap is 3.4 electron volt for gallium nitride, 3.2 electron volt for silicon carbide, 4.5 to 4.8 electron volt for gallium oxide, and 5.5 electron volt for diamond.
  • the band gap of the substrate layer 1 is preferably 4.0 electron volts or more, and more preferably 5.0 electron volts or more.
  • Diamond crystals are particularly preferable as the substrate layer 1. Further, as the diamond crystal, for example, KENZAN Diamond (registered trademark) of Adamant Namiki Precision Jewelery Co., Ltd. can be preferably used.
  • the substrate layer 1 has a hydrogen adsorption layer 12.
  • the hydrogen adsorption layer 12 can be formed by irradiating the substrate layer 1 with hydrogen plasma. By providing the hydrogen adsorption layer 12, higher mobility can be achieved. Further, by growing the diamond crystal with the microwave plasma CVD apparatus, it is possible to obtain the diamond crystal which becomes the substrate layer 1 having the hydrogen adsorption layer.
  • the multilayer film structure 10 (101) has a first insulating layer 2.
  • the first insulating layer 2 is arranged on the substrate layer 1 so as to be in contact with the substrate layer 1.
  • the first insulating layer 2 is arranged so as to be in contact with the layer provided with the hydrogen adsorption layer 12.
  • the first insulating layer can be an oxide or fluoride layer in the same manner as the second insulating layer. These can be layers of oxides or fluorides of metal or silicon. A layer using these materials is called an insulating layer because it limits the movement of electrons and can substantially eliminate the movement of electrons through the layer by making the layer thicker. Further, as the insulating layer, a layer having a wider bandgap than the bandgap of the substrate layer is used.
  • oxides examples include aluminum oxide (Al 2 O 3 ), magnesium oxide (MgO), hafnium oxide (HfO 2 ), silicon dioxide (SiO 2 ), strontium titanate (SrTiO 3 ), and gallium oxide (SrTiO 3).
  • Ga 2 O 3 ), lithium niobate (LiNbO 3 ), lead zirconate titanate (PZT) and the like can be used.
  • fluorides for example, calcium fluoride (CaF 2 ), magnesium fluoride (MgF 2 ) and the like can be used.
  • the first insulating layer 2 is provided between the substrate layer 1 and the adsorption layer 3 in order to prevent the diffusion of holes and carriers.
  • the thickness of the first insulating layer is preferably 4 to 12 nm. More preferably, it is 6 to 10 nm. Further, from the viewpoint of ease of handling during manufacturing, adjustment of film quality, compatibility with the substrate layer 1, etc., it is particularly preferable to use aluminum oxide, and it is particularly preferable that the thickness is about 8 nm. These thicknesses can be measured with a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • the multilayer film structure 10 (101) has an adsorption layer 3.
  • the adsorption layer 3 is arranged on the first insulating layer 2 so as to be in contact with the first insulating layer 2.
  • the adsorption layer 3 is a layer on which any gas molecule selected from the group consisting of nitrogen dioxide (NO 2 ), nitric oxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ) is adsorbed. ..
  • NO 2 nitrogen dioxide
  • NO nitric oxide
  • SO 2 sulfur dioxide
  • O 3 ozone
  • the multilayer film structure 10 (101) has a second insulating layer 4.
  • the second insulating layer 4 is arranged on the adsorption layer 3 so as to be in contact with the adsorption layer 3.
  • the same material as that of the first insulating layer 2 can be used.
  • the thickness of the second insulating layer 4 is preferably 4 to 100 nm.
  • the upper limit of the thickness of the second insulating layer 4 may be 50 nm or less, 20 nm or less, 12 nm or less, 10 nm or less. Further, the lower limit of the thickness of the second insulating layer 4 may be 6 nm or more.
  • the multilayer film structure 10 (101) has a gate electrode 5.
  • the gate electrode 5 is arranged on the second insulating layer 4 so as to be in contact with the second insulating layer 4.
  • the gate electrode is preferably a metal layer.
  • gold Au
  • Ti laminated film of gold and titanium
  • Al Al / Ti / Au in order from the lower layer
  • Al Al / Ti / Au in order from the lower layer
  • the multilayer film structure 102 can have other structures such as a source electrode 8 and a drain electrode 9.
  • the multilayer film structure 10 (101, 102) can be used for an electronic element or the like which is an element using electric conduction.
  • it can be used for transistors, diodes, MEMS and the like.
  • FIG. 3 is a schematic diagram for explaining an example of a manufacturing process of the multilayer film structure of the present invention.
  • the multilayer film structure 102 can be manufactured by steps 1 to 6.
  • FIG. 3A Step 1 First, the substrate layer 1 is manufactured.
  • the substrate layer of diamond crystals can be grown in a CVD apparatus.
  • FIG. 3B Step 2 Next, the hydrogen adsorption layer 12 is provided on the substrate layer 1.
  • the hydrogen adsorption layer 12 can be formed by irradiating the substrate layer 1 with hydrogen plasma.
  • FIG. 3A Step 1 First, the substrate layer 1 is manufactured.
  • the substrate layer of diamond crystals can be grown in a CVD apparatus.
  • FIG. 3B Step 2 Next, the hydrogen adsorption layer 12 is provided on the substrate layer 1.
  • Step 4 Next, the first insulating layer 2 is provided between the source electrode 8 and the drain electrode 9 so as to be in contact with the hydrogen adsorption layer 12 of the substrate layer 1.
  • the first insulating layer 2 can be provided by the first deposition step of depositing a material such as aluminum oxide (Al 2 O 3 ).
  • FIG. 3 (f) Step 6 Then, by providing the gate electrode 5 on the second insulating layer 4, the multilayer film structure 102 can be obtained.
  • the hydrogen adsorption layer forming step is a step of forming a hydrogen adsorption layer on the surface of the substrate layer 1 having a band gap of 3.0 electron volts or more.
  • the hydrogen adsorption layer can be formed, for example, by irradiating the substrate layer 1 with hydrogen plasma.
  • the first deposition step is preferably the first deposition step of depositing the member forming the first insulating layer.
  • the first deposition step is to deposit aluminum oxide (Al 2 O 3 ), and it is preferable that the sample temperature is 50 to 300 ° C. The temperature may be 100 to 250 ° C.
  • the forming step is selected from the group consisting of nitrogen dioxide (NO 2 ), nitric oxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ) on the surface of the first insulating layer. It is preferable that the step is a forming step in which gas molecules are brought into contact with each other to form an adsorption layer.
  • the forming step is for adsorbing gas molecules, and the concentration of the gas molecular gas is preferably 0.2% or more.
  • the supply time of gas molecules is preferably 3 to 20 minutes.
  • the degree of vacuum is preferably 6.67 kPa to 26.7 kPa (50 to 200 torr).
  • the degree of vacuum is particularly preferably 14.7 kPa to 18.7 kPa (110 to 140 torr).
  • the sample temperature is preferably 50 to 200 ° C. in order to stabilize the gas molecules when they are adsorbed.
  • the second deposition step is to deposit a member forming the second insulating layer on the surface of the adsorption layer.
  • the second deposition step is for depositing aluminum oxide (Al 2 O 3 ), and it is preferable that the sample temperature is 50 to 200 ° C.
  • these hydrogen adsorption layer forming steps, the first deposition step, the forming step, and the second deposition step are performed in the same treatment tank, and the atmosphere thereof is a controlled atmosphere.
  • the atmosphere can be controlled by nitrogen substitution, vacuum, or the like. Conventionally, it has been considered preferable to carry out the deposition step in the atmosphere, but in the present invention, it can be carried out with nitrogen substitution or vacuum. Therefore, in the same tank as the treatment tank in which the hydrogen adsorption layer forming step was performed, the subsequent deposition step, formation step, etc. can be performed, the manufacturing process can be easily managed, and the one with excellent quality is stable. Can be manufactured.
  • Example 1 An example of producing a multilayer film structure corresponding to the multilayer film structure 102 of FIG. 3 will be described in the following steps.
  • the substrate layer 1 Kenzan diamond (registered trademark) manufactured by Adamant Namiki Precision Jewel Co., Ltd. was used.
  • the substrate layer 1 was irradiated with hydrogen plasma (represented by H) in the reactor of the microwave plasma CVD apparatus to form the hydrogen adsorption layer 12.
  • the hydrogen adsorption layer 12 was formed by leaving the microwave at a frequency of 2.45 GHz, an output of 750 W, a reaction pressure of 50 Torr (6.67 kPa), and a hydrogen supply amount of 300 cm for 10 minutes.
  • the source electrode 8 and the drain electrode 9 were formed by vacuum deposition.
  • the sample is supplied with trimethylaluminum and H 2 O alternately in vacuum by the atomic layer deposition (ALD) method, and the aluminum oxide layer (Al 2 O 3 film) is first insulated. It was deposited as layer 2.
  • ALD atomic layer deposition
  • NO 2 having a concentration of 2% was supplied to form the NO 2 adsorption layer 3.
  • the aluminum oxide layer (Al 2 O 3 film) was deposited again as the second insulating layer 4 by using the ALD method again.
  • an Au film to be the gate electrode layer 5 is deposited.
  • FIG. 6 shows an outline of a production example according to Example 1.
  • Al 2 O 3-8 nm @ 230 ° C.” it means that a layer of aluminum oxide is deposited at 230 ° C. by 8 nm.
  • NO 2 @ 80 ° C.” means that the NO 2 gas was adsorbed at 80 ° C.
  • Al 2 O 3-8 nm @ 80 ° C.” means that a layer of aluminum oxide was deposited at 80 ° C. by 8 nm.
  • FIGS. 7 and 8 show gates based on the sheet resistance (Sheet Resistance (k ⁇ / sq.)) Of the manufactured sample and the drain current (( IDS (mA / mm)) with respect to the drain voltage (output voltage (V DS (V))). The results of evaluating the voltage dependence are shown. These measurements were performed using a "B1505A power device analyzer / curve tracer" manufactured by KEYSIGHT TECHNOLOGIES.
  • FIG. 7 shows the results of examining the thickness and treatment temperature of the aluminum oxide layer as the first insulating layer.
  • the configurations shown in FIG. 6 were evaluated except for the changed conditions.
  • the first insulating layer had the lowest sheet resistance, especially at 8 nm.
  • FIG. 8 shows the results of examining the treatment temperature in the forming step of forming the NO 2 adsorption layer.
  • the temperature at which the NO 2 adsorption layer was formed was about 80 ° C.
  • the description of (80 ° C., 80 ° C.), (230 ° C., 80 ° C.), and (230 ° C., 230 ° C.) in the graph relates to the test conditions of each measurement point in the graph. ..
  • the left side in parentheses is the sample temperature when the first aluminum oxide layer (first Al 2 O 3 ) is deposited, and the right side in parentheses is the sample temperature when the second aluminum oxide layer (second Al 2 O 3 ) is deposited.
  • Sample temperature For example, in (80 ° C., 80 ° C.), the sample temperature at the time of depositing the first aluminum oxide layer is 80 ° C., and the sample temperature at the time of depositing the second aluminum oxide layer is 80 ° C.
  • FIG. 9 is a result of evaluating the gate voltage dependence of the multilayer film structure having the configuration shown on the left side of FIG. 9.
  • the temperature (X ° C.) is 80 ° C., 230 ° C., and 330 ° C. as the deposition condition of the first insulating layer.
  • the results of measuring the maximum drain current of the FET having a multilayer structure manufactured at these manufacturing temperatures are shown on the right side of FIG.
  • the multilayer film structure of the present invention can be used for electronic elements such as transistors and diodes, and is industrially useful.
  • Substrate layer 10 101, 102, 20, 201 Multilayer membrane structure 12 Hydrogen adsorption layer 2 First insulation layer 3 Adsorption layer 4 Second insulation layer 5 Gate electrode 8 Source electrode 9 Drain electrode

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Abstract

Provided is a multilayer film structure which improves the mobility of a substrate having a large band gap such as a diamond crystal and not exhibiting mobility. This multilayer film structure is suitable for electronic elements such as transistors and diodes.　A multilayer film structure 10 includes: a substrate layer 1 having a band gap of at least 3.0 electron volts; a first insulating layer 2 disposed on the substrate layer 1; an adsorption layer 3 of any gas molecule selected from the group consisting of nitrogen dioxide (NO2), nitrogen monoxide (NO), sulfur dioxide (SO2), and ozone (O3), the adsorption layer 3 being disposed on the first insulating layer 2; a second insulating layer 4 disposed on the adsorption layer 3; and a gate electrode layer 5 disposed on the second insulating layer 4.

Description

多層膜構造体、多層膜構造体の製造方法、および電子素子Multilayer film structure, manufacturing method of multilayer film structure, and electronic device
　本発明は多層膜構造体に関する。また、多層膜構造体の製造方法に関する。また、多層膜構造体を有する電子素子に関する。 The present invention relates to a multilayer film structure. The present invention also relates to a method for manufacturing a multilayer film structure. Further, the present invention relates to an electronic device having a multilayer film structure.
　ダイヤモンド半導体は、５．４７エレクトロンボルトというシリコン半導体の約５倍のバンドギャップを持ち、絶縁耐圧は１０ＭＶ／ｃｍ以上と、シリコンの０．３ＭＶ／ｃｍの３３倍以上の値を持つため、高効率、大電力、高周波トランジスタ用の半導体材料として、期待されている。また、ダイヤモンドに限らず、他のバンドギャップが大きい素材が提案されている。 Diamond semiconductors have a bandgap of 5.47 electron volts, which is about five times that of silicon semiconductors, and have an insulation withstand voltage of 10 MV / cm or more, which is 33 times or more the value of 0.3 MV / cm of silicon, so they are highly efficient. It is expected as a semiconductor material for high power and high frequency transistors. In addition to diamond, other materials with a large bandgap have been proposed.
　本発明者らは、水素吸着したダイヤモンド結晶表面に二酸化窒素（ＮＯ2）吸着層を設けることにより、ホールの面濃度１ｘ１０14ｃｍ-2を得ている。また、電界効果トランジスタ（Ｆｉｅｌｄ　ｅｆｆｅｃｔ　ｔｒａｎｓｉｓｔｏｒ，ＦＥＴ）での移動度は３２ｃｍ2／Ｖｓが得られている。しかし、この移動度は、ダイヤモンド本来の移動度（電子４５００ｃｍ2／Ｖｓ，ホール３８００ｃｍ2／Ｖｓ）より著しく低い。このように、バンドギャップが大きく、絶縁耐圧などからも、より優れた移動度が期待されている半導体でも、その半導体材料の本来の性質を表せないでいる。 The present inventors have obtained a hole surface concentration of 1 x 10 14 cm -2 by providing a nitrogen dioxide (NO 2 ) adsorption layer on the surface of a hydrogen-adsorbed diamond crystal. Further, the mobility of the field effect transistor (FET) is 32 cm 2 / Vs. However, this mobility is significantly lower than the original mobility of diamond (electrons 4500 cm 2 / Vs, holes 3800 cm 2 / Vs). As described above, even a semiconductor having a large bandgap and expected to have higher mobility due to its dielectric strength and the like cannot express the original properties of the semiconductor material.
　非特許文献１において、嘉数が、ＮＯ2分子は水素終端ダイヤモンドに対し、アクセプタ不純物となり、ホールを生成することを報告している。非特許文献１に関する従来技術について、図４、５を用いて、ＦＥＴのゲート構造でのホールキャリアの電気伝導について説明する。この多層膜構造体２０（２０１）は、ダイヤモンド結晶１を基板として、その表面に水素吸着層１２があり、そこにＮＯ2吸着層３を形成し、Ａｌ2Ｏ3層４を堆積させ、最後にゲート金属層５を堆積していた。また、非特許文献２～３も、ダイヤモンドを利用するトランジスタについて開示している。 In Non-Patent Document 1, Kazu reports that NO 2 molecule becomes an acceptor impurity for hydrogen-terminated diamond and forms holes. Regarding the prior art relating to Non-Patent Document 1, the electrical conduction of the whole carrier in the gate structure of the FET will be described with reference to FIGS. 4 and 5. In this multilayer film structure 20 (201), a diamond crystal 1 is used as a substrate, and a hydrogen adsorption layer 12 is provided on the surface thereof, a NO 2 adsorption layer 3 is formed therein, an Al 2 O 3 layer 4 is deposited, and finally. The gate metal layer 5 was deposited on the surface. In addition, Non-Patent Documents 2 and 3 also disclose transistors using diamond.
　特許文献１は、ダイヤモンド基板と、前記ダイヤモンド基板の表面を水素原子で終端することにより形成された表面層と、前記表面層を大気中に曝すことにより前記表面層上に形成された、大気中の分子からなる第一の吸着層と、前記第一の吸着層上に互いに離間して形成された、ソース電極及びドレイン電極と、前記ソース電極と前記ドレイン電極との間に露出した、前記第一の吸着層の上部全体を覆うように形成された、ＮＯ2分子からなる第二の吸着層と、前記第二の吸着層上に形成された、酸素を含む化合物からなる保護層と、前記保護層上に、前記ソース電極と前記ドレイン電極との間に離間して形成された、ゲート電極とを備えたことを特徴とするダイヤモンド電界効果トランジスタを開示している。 Patent Document 1 describes a diamond substrate, a surface layer formed by terminating the surface of the diamond substrate with hydrogen atoms, and an atmosphere formed on the surface layer by exposing the surface layer to the atmosphere. The first adsorption layer made of the above-mentioned molecules, the source electrode and the drain electrode formed on the first adsorption layer at a distance from each other, and the first exposed between the source electrode and the drain electrode. A second adsorption layer made of NO 2 molecules formed so as to cover the entire upper part of one adsorption layer, a protective layer made of an oxygen-containing compound formed on the second adsorption layer, and the above-mentioned Disclosed is a diamond electric field effect transistor characterized by having a gate electrode formed on the protective layer at a distance between the source electrode and the drain electrode.
特許第５７５９３９８号公報Japanese Patent No. 5759398
　特許文献１や非特許文献１のように、ダイヤモンド素子などの基板材料の本来の移動度を表す手法が検討されている。例えば、ホールを生成したＮＯ2分子アクセプタは、負に帯電したイオン化アクセプタになるため、ダイヤモンド結晶層とＡｌ2Ｏ3膜の間の、水素吸着層、ＮＯ2吸着層中を走行するホールは、ＮＯ2分子イオン化アクセプタによるイオン化不純物散乱機構や、ダイヤモンド表面に不可避の表面粗さによる表面散乱機構により、移動度は、ダイヤモンド本来の移動度３８００ｃｍ2／Ｖｓに対して著しく低い移動度しか示すことができない。その結果として、チャンネル抵抗も高く、ダイヤモンド本来の物性を示すことができなかった。 As in Patent Document 1 and Non-Patent Document 1, methods for expressing the original mobility of a substrate material such as a diamond element are being studied. For example, the NO 2 molecule acceptor that generated the hole becomes a negatively charged ionization acceptor, so the hole running in the hydrogen adsorption layer and the NO 2 adsorption layer between the diamond crystal layer and the Al 2 O 3 film is Due to the ionization impurity scattering mechanism by the NO 2 molecule ionization acceptor and the surface scattering mechanism due to the inevitable surface roughness on the diamond surface, the mobility is significantly lower than the original mobility of diamond, 3800 cm 2 / Vs. Can not. As a result, the channel resistance was also high, and it was not possible to show the original physical characteristics of diamond.
　また、前述の手法のほかにも、ダイヤモンド素子の移動度を向上させることが検討されているが、十分に移動度を向上させることはできていなかった。また、ダイヤモンドに限らず、大きなバンドギャップを有し高い移動度を有する基板であっても、同様に、その移動度を十分に発揮させることができないでいる。 In addition to the above-mentioned method, it has been considered to improve the mobility of the diamond element, but the mobility could not be sufficiently improved. Further, not only diamond but also a substrate having a large band gap and high mobility cannot sufficiently exhibit the mobility.
　係る状況下、本発明は、移動度を向上させた多層膜構造体およびその製造方法等を提供することを目的とする。 Under such circumstances, an object of the present invention is to provide a multilayer film structure having improved mobility, a method for manufacturing the same, and the like.
　本発明者は、上記課題を解決すべく鋭意研究を重ねた結果、下記の発明が上記目的に合致することを見出し、本発明に至った。すなわち、本発明は、以下の発明に係るものである。 As a result of diligent research to solve the above problems, the present inventor has found that the following invention meets the above object, and has reached the present invention. That is, the present invention relates to the following invention.
　＜１＞　バンドギャップが、３．０エレクトロンボルト以上の基板層と、前記基板層の上に配置された第一の絶縁層と、前記第一の絶縁層の上に配置された、二酸化窒素（ＮＯ2）、一酸化窒素（ＮＯ）、二酸化硫黄（ＳＯ2）、およびオゾン（Ｏ3）からなる群から選択されるいずれかの気体分子の吸着層と、前記吸着層の上に配置された第二の絶縁層と、前記第二の絶縁層の上に配置されたゲート電極層と、を有する、多層膜構造体。
　＜２＞　前記基板層が、窒化ガリウム（ＧａＮ）、炭化シリコン（ＳｉＣ）、酸化ガリウム（Ｇａ2Ｏ3）、およびダイヤモンドからなる群から選択されるいずれかの結晶を含み、前記第一の絶縁層および前記第二の絶縁層が、酸化物またはフッ化物の層であり、前記ゲート電極層が、金属の層である、前記＜１＞に記載の多層膜構造体。
　＜３＞　前記基板層が、水素吸着層を有するダイヤモンド結晶の層であり、前記第一の絶縁層が、厚み４～１２ｎｍの酸化アルミニウム（Ａｌ2Ｏ3）の層であり、前記吸着層が、二酸化窒素（ＮＯ2）吸着層であり、前記第二の絶縁層が、厚み４～１００ｎｍの酸化アルミニウム（Ａｌ2Ｏ3）の層であり、前記ゲート電極が、金属の層である、前記＜１＞に記載の多層膜構造体。
　＜４＞　前記＜１＞～＜３＞のいずれかに記載の多層膜構造体を含む、電子素子。 <1> A substrate layer having a band gap of 3.0 electron volt or more, a first insulating layer arranged on the substrate layer, and nitrogen dioxide (nitrogen dioxide) arranged on the first insulating layer. An adsorbed layer of any gas molecule selected from the group consisting of NO 2 ), nitrogen monoxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ), and placed on top of the adsorbed layer. A multilayer film structure having a second insulating layer and a gate electrode layer arranged on the second insulating layer.
<2> The substrate layer contains any crystal selected from the group consisting of gallium nitride (GaN), silicon carbide (SiC), gallium oxide (Ga 2 O 3 ), and diamond, and the first insulation. The multilayer film structure according to <1>, wherein the layer and the second insulating layer are layers of oxide or fluoride, and the gate electrode layer is a layer of metal.
<3> The substrate layer is a layer of diamond crystals having a hydrogen adsorption layer, the first insulating layer is a layer of aluminum oxide (Al 2 O 3 ) having a thickness of 4 to 12 nm, and the adsorption layer is. , The nitrogen dioxide (NO 2 ) adsorption layer, the second insulating layer is a layer of aluminum oxide (Al 2 O 3 ) having a thickness of 4 to 100 nm, and the gate electrode is a metal layer. The multilayer film structure according to <1>.
<4> An electronic device including the multilayer film structure according to any one of <1> to <3>.
　＜５＞　バンドギャップが、３．０エレクトロンボルト以上の基板層の表面に、制御された雰囲気下で、第一の絶縁層を形成する部材を堆積させる第一の堆積工程と、前記第一の絶縁層の表面に、制御された雰囲気下で、二酸化窒素（ＮＯ2）、一酸化窒素（ＮＯ）、二酸化硫黄（ＳＯ2）、およびオゾン（Ｏ3）からなる群から選択されるいずれかの気体分子を接触させて吸着層を形成する形成工程と、前記吸着層の表面に、制御された雰囲気下で、第二の絶縁層を形成する部材を堆積させる第二の堆積工程と、を有する、多層膜構造体の製造方法。
　＜６＞　前記第一の堆積工程の前に、前記基板層の表面に、水素プラズマを照射することで、水素吸着層を形成させる水素吸着層形成工程を有する、前記＜５＞に記載の製造方法。
　＜７＞　前記水素吸着形成工程、前記第一の堆積工程、前記形成工程、および前記第二の堆積工程が、同一の処理槽内で行われ、前記雰囲気が、真空または窒素置換された雰囲気である、前記＜６＞に記載の製造方法。
　＜８＞　前記第一の堆積工程が、酸化アルミニウム（Ａｌ2Ｏ3）を堆積させるものであり、試料温度は５０～３００℃で堆積させるものであり、前記形成工程が、二酸化窒素（ＮＯ2）を吸着させるものであり、前記形成工程において、ＮＯ2ガスの濃度が０．２％以上であり、供給時間が３～２０分であり、真空度は６．６７ｋＰａ～２６．７ｋＰａであり、かつ、試料温度は５０～２００℃で吸着させるものであり、前記第二の堆積工程が、酸化アルミニウム（Ａｌ2Ｏ3）を堆積させるものであり、試料温度は５０～２００℃で堆積させるものである、前記＜５＞～＜７＞のいずれかに記載の製造方法。 <5> The first deposition step of depositing a member forming the first insulating layer on the surface of a substrate layer having a band gap of 3.0 electron volt or more in a controlled atmosphere, and the first. On the surface of the insulating layer, under a controlled atmosphere, any one selected from the group consisting of nitrogen dioxide (NO 2 ), nitrogen monoxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ). It has a forming step of contacting gas molecules to form an adsorption layer, and a second deposition step of depositing a member forming a second insulating layer on the surface of the adsorption layer under a controlled atmosphere. , A method for manufacturing a multilayer film structure.
<6> The production according to <5>, which comprises a hydrogen adsorption layer forming step of irradiating the surface of the substrate layer with hydrogen plasma to form a hydrogen adsorption layer before the first deposition step. Method.
<7> The hydrogen adsorption forming step, the first deposition step, the forming step, and the second deposition step are performed in the same treatment tank, and the atmosphere is a vacuum or nitrogen-substituted atmosphere. The manufacturing method according to <6> above.
<8> The first deposition step is for depositing aluminum oxide (Al 2 O 3 ), the sample temperature is 50 to 300 ° C., and the forming step is nitrogen dioxide (NO 2 ). ) Is adsorbed, the concentration of NO 2 gas is 0.2% or more, the supply time is 3 to 20 minutes, and the degree of vacuum is 6.67 kPa to 26.7 kPa in the forming step. Moreover, the sample temperature is 50 to 200 ° C., the second deposition step is to deposit aluminum oxide (Al 2 O 3 ), and the sample temperature is 50 to 200 ° C. The production method according to any one of <5> to <7>.
　本発明によれば、移動度を向上させた多層膜構造体およびその製造方法等が提供される。 According to the present invention, a multilayer film structure having improved mobility, a method for manufacturing the same, and the like are provided.
本発明の多層膜構造体の概要図である。It is a schematic diagram of the multilayer film structure of this invention. 本発明の多層膜構造体の他の概要図である。It is another schematic diagram of the multilayer film structure of this invention. 本発明の多層膜構造体の製造工程を説明するための概要図である。It is a schematic diagram for demonstrating the manufacturing process of the multilayer film structure of this invention. 従来の多層膜構造体の概要図である。It is a schematic diagram of the conventional multilayer film structure. 従来の多層膜構造体の製造工程を説明するための概要図である。It is a schematic diagram for demonstrating the manufacturing process of the conventional multilayer film structure. 実施例に係る多層膜構造体を説明するための概要図である。It is a schematic diagram for demonstrating the multilayer film structure which concerns on Example. 実施例に係る多層膜構造体の評価結果を示すグラフである。It is a graph which shows the evaluation result of the multilayer film structure which concerns on Example. 実施例に係る多層膜構造体の評価結果を示すグラフである。It is a graph which shows the evaluation result of the multilayer film structure which concerns on Example. 実施例に係る多層膜構造体の評価結果を示すグラフである。It is a graph which shows the evaluation result of the multilayer film structure which concerns on Example.
　以下に本発明の実施の形態を詳細に説明するが、以下に記載する構成要件の説明は、本発明の実施態様の一例（代表例）であり、本発明はその要旨を変更しない限り、以下の内容に限定されない。なお、本明細書において「～」という表現を用いる場合、その前後の数値を含む表現として用いる。 Hereinafter, embodiments of the present invention will be described in detail, but the description of the constituent elements described below is an example (representative example) of the embodiments of the present invention, and the present invention is described below unless the gist thereof is changed. It is not limited to the contents of. In addition, when the expression "-" is used in this specification, it is used as an expression including numerical values before and after it.
［本発明の多層膜構造体］
　本発明の多層膜構造体は、バンドギャップが、３．０エレクトロンボルト以上の基板層と、前記基板層の上に配置された第一の絶縁層と、前記第一の絶縁層の上に配置された、二酸化窒素（ＮＯ2）、一酸化窒素（ＮＯ）、二酸化硫黄（ＳＯ2）、およびオゾン（Ｏ3）からなる群から選択されるいずれかの気体分子の吸着層と、前記吸着層の上に配置された第二の絶縁層と、前記第二の絶縁層の上に配置されたゲート電極層を有する。 [Multilayer film structure of the present invention]
The multilayer film structure of the present invention has a substrate layer having a band gap of 3.0 electron volt or more, a first insulating layer arranged on the substrate layer, and an arrangement on the first insulating layer. An adsorption layer of any gas molecule selected from the group consisting of nitrogen dioxide (NO 2 ), nitrogen monoxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ), and the adsorption layer. It has a second insulating layer arranged on the above and a gate electrode layer arranged on the second insulating layer.
［本発明の多層膜構造体の製造方法］
　本発明の多層膜構造体の製造方法は、バンドギャップが、３．０エレクトロンボルト以上の基板層の表面に、制御された雰囲気下で、第一の絶縁層を形成する部材を堆積させる第一の堆積工程と、前記第一の絶縁層の表面に、制御された雰囲気下で、二酸化窒素（ＮＯ2）、一酸化窒素（ＮＯ）、二酸化硫黄（ＳＯ2）、およびオゾン（Ｏ3）からなる群から選択されるいずれかの気体分子を接触させて吸着層を形成する形成工程と、前記吸着層の表面に、制御された雰囲気下で、第二の絶縁層を形成する部材を堆積させる第二の堆積工程と、を有する。 [Method for manufacturing a multilayer film structure of the present invention]
In the method for producing a multilayer film structure of the present invention, a member forming a first insulating layer is deposited on the surface of a substrate layer having a band gap of 3.0 electron volt or more under a controlled atmosphere. From nitrogen dioxide (NO 2 ), nitrogen monoxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ) in a controlled atmosphere on the surface of the first insulating layer. A forming step of contacting any gas molecule selected from the group to form an adsorption layer, and depositing a member forming a second insulating layer on the surface of the adsorption layer under a controlled atmosphere. It has a second deposition step.
　本発明の多層膜構造体は、基板層の本来の移動度に近い、優れた移動度を発揮することができる。本発明の多層膜構造体の製造方法により、本発明の多層膜構造体を製造することができ、本願においてそれぞれに対応する構成は相互に利用することができる。 The multilayer film structure of the present invention can exhibit excellent mobility close to the original mobility of the substrate layer. By the method for producing a multilayer film structure of the present invention, the multilayer film structure of the present invention can be produced, and the configurations corresponding to each can be mutually used in the present application.
　本発明は、ホールが走行する層とホールを生成する二酸化窒素（ＮＯ2）分子アクセプタの層の間に、新たに酸化アルミニウム（Ａｌ2Ｏ3）層を設けることにより、ホール走行層と負にイオン化したＮＯ2分子を空間的に分離することにより、イオン化不純物散乱や表面散乱機構を無くすことができ、ホールがダイヤモンドなどの基板の本来の高移動度を生じることができる。 The present invention is negative from the hole traveling layer by providing a new aluminum oxide (Al 2 O 3 ) layer between the layer on which the hole travels and the layer of the nitrogen dioxide (NO 2 ) molecule acceptor that produces the hole. By spatially separating the ionized NO 2 molecules, the ionized impurity scattering and surface scattering mechanisms can be eliminated, and the holes can generate the original high mobility of a substrate such as diamond.
　本発明をダイヤモンド基板に適用することで、従来のダイヤモンド基板によるトランジスタでの移動度３０ｃｍ2／Ｖｓを、ダイヤモンド本来の移動度３８００ｃｍ2／Ｖｓと１００倍以上に上昇させることができる。その結果、シート抵抗を１／１００以下に低減することができる。また、電流値を１００倍以上に増加させることができる。また、トランジスタの制御できる電力である有能電力を１００倍以上に上昇することができる。その結果、大電力用のシリコン半導体を凌駕する半導体デバイスが生まれる。 By applying the present invention to a diamond substrate, the mobility of a conventional diamond substrate in a transistor of 30 cm 2 / Vs can be increased 100 times or more to the original mobility of diamond of 3800 cm 2 / Vs. As a result, the sheet resistance can be reduced to 1/100 or less. In addition, the current value can be increased 100 times or more. In addition, the competent power, which is the power that can be controlled by the transistor, can be increased 100 times or more. As a result, semiconductor devices that surpass silicon semiconductors for high power consumption will be born.
［多層膜構造体１０、１０１］
　図１は、本発明の第一の実施形態に係る多層膜構造体１０の概要図である。多層膜構造体１０は、基板を最下層としてみたとき、下から順に、基板層１と、第一の絶縁層２と、吸着層３と、第二の絶縁層４と、ゲート電極５を有する。この多層膜構造体１０は、各種電子素子に用いられる。 [Multilayer film structures 10, 101]
FIG. 1 is a schematic view of the multilayer film structure 10 according to the first embodiment of the present invention. The multilayer film structure 10 has a substrate layer 1, a first insulating layer 2, an adsorption layer 3, a second insulating layer 4, and a gate electrode 5 in this order from the bottom when the substrate is viewed as the lowest layer. .. This multilayer film structure 10 is used for various electronic devices.
　また、図２は、本発明の第二の実施形態に係る多層膜構造体１０１の概要図である。多層膜構造体１０１は、多層膜構造体１０の構造に準じるもので、基板１の表面に水素吸着処理を行って、水素吸着層１２を設けた構造である。 Further, FIG. 2 is a schematic view of the multilayer film structure 101 according to the second embodiment of the present invention. The multilayer film structure 101 conforms to the structure of the multilayer film structure 10, and has a structure in which the surface of the substrate 1 is subjected to hydrogen adsorption treatment to provide the hydrogen adsorption layer 12.
［基板層１］
　多層膜構造体１０（１０１）は、基板層１を有する。基板層１は、バンドギャップが、３．０エレクトロンボルト以上のものを用いる。このようなバンドギャップが大きい基板は、従来の多層膜構造体では、そのバンドギャップ等から期待される移動度を発揮できていなかった。しかし、本発明の多層膜構造体１０（１０１）の基板層として用いることで、その優れた移動度を発揮できる。 [Board layer 1]
The multilayer film structure 10 (101) has a substrate layer 1. The substrate layer 1 has a bandgap of 3.0 electron volts or more. Such a substrate having a large bandgap has not been able to exhibit the mobility expected from the bandgap or the like in the conventional multilayer film structure. However, by using it as the substrate layer of the multilayer film structure 10 (101) of the present invention, its excellent mobility can be exhibited.
　基板層１は、窒化ガリウム（ＧａＮ）、炭化シリコン（ＳｉＣ）、酸化ガリウム（Ｇａ2Ｏ3）、およびダイヤモンドからなる群から選択されるいずれかの結晶を含むものとすることができる。この結晶は、実質的にいずれかのものからなるものとしてもよいし、前述のものを組み合わせたものや、これらに他のものを組み合わせたものを用いてもよい。 The substrate layer 1 can include any crystal selected from the group consisting of gallium nitride (GaN), silicon carbide (SiC), gallium oxide (Ga 2 O 3 ), and diamond. This crystal may be substantially any one, or a combination of the above-mentioned crystals or a combination of these and other crystals may be used.
　バンドギャップは、窒化ガリウムは３．４エレクトロンボルト、炭化シリコンは３．２エレクトロンボルト、酸化ガリウムは４．５～４．８エレクトロンボルト、ダイヤモンドは５．５エレクトロンボルトである。基板層１のバンドギャップは、４．０エレクトロンボルト以上が好ましく、５．０エレクトロンボルト以上がさらに好ましい。基板層１としては、ダイヤモンド結晶が特に好ましい。また、ダイヤモンド結晶は、例えば、アダマンド並木精密宝石株式会社のＫＥＮＺＡＮ　Ｄｉａｍｏｎｄ（登録商標）を好ましく用いることができる。 The bandgap is 3.4 electron volt for gallium nitride, 3.2 electron volt for silicon carbide, 4.5 to 4.8 electron volt for gallium oxide, and 5.5 electron volt for diamond. The band gap of the substrate layer 1 is preferably 4.0 electron volts or more, and more preferably 5.0 electron volts or more. Diamond crystals are particularly preferable as the substrate layer 1. Further, as the diamond crystal, for example, KENZAN Diamond (registered trademark) of Adamant Namiki Precision Jewelery Co., Ltd. can be preferably used.
［水素吸着層１２］
　多層膜構造体１０１に示すように、基板層１は、水素吸着層１２を有するものとすることが好ましい。水素吸着層１２は、基板層１に水素プラズマを照射することで形成することができる。水素吸着層１２を設けることで、より高い移動度を達成することができる。また、マイクロ波プラズマＣＶＤ装置でダイヤモンド結晶を成長させることで、水素吸着層を有する基板層１となるダイヤモンド結晶とすることができる。 [Hydrogen adsorption layer 12]
As shown in the multilayer film structure 101, it is preferable that the substrate layer 1 has a hydrogen adsorption layer 12. The hydrogen adsorption layer 12 can be formed by irradiating the substrate layer 1 with hydrogen plasma. By providing the hydrogen adsorption layer 12, higher mobility can be achieved. Further, by growing the diamond crystal with the microwave plasma CVD apparatus, it is possible to obtain the diamond crystal which becomes the substrate layer 1 having the hydrogen adsorption layer.
［第一の絶縁層２］
　多層膜構造体１０（１０１）は、第一の絶縁層２を有する。第一の絶縁層２は、基板層１の上に、基板層１と接するように配置される。基板層１が、水素吸着層１２を有するものとする場合、水素吸着層１２を設けた層と接するように、第一の絶縁層２は配置される。 [First Insulation Layer 2]
The multilayer film structure 10 (101) has a first insulating layer 2. The first insulating layer 2 is arranged on the substrate layer 1 so as to be in contact with the substrate layer 1. When the substrate layer 1 has the hydrogen adsorption layer 12, the first insulating layer 2 is arranged so as to be in contact with the layer provided with the hydrogen adsorption layer 12.
　第一の絶縁層は、第二の絶縁層と同様に、酸化物またはフッ化物の層とすることができる。これらは金属やシリコンの、酸化物またはフッ化物の層とすることができる。これらの材質を用いた層は、電子の移動を制限し、厚くすることで実質的にその層を介する電子の移動を無くすことができるため絶縁層と呼ぶ。また、絶縁層には、基板層のバンドギャップよりも、バンドギャップが広いものを用いる。 The first insulating layer can be an oxide or fluoride layer in the same manner as the second insulating layer. These can be layers of oxides or fluorides of metal or silicon. A layer using these materials is called an insulating layer because it limits the movement of electrons and can substantially eliminate the movement of electrons through the layer by making the layer thicker. Further, as the insulating layer, a layer having a wider bandgap than the bandgap of the substrate layer is used.
　これらの酸化物としては、例えば、酸化アルミニウム（Ａｌ2Ｏ3）や、酸化マグネシウム（ＭｇＯ）、酸化ハフニウム（ＨｆＯ2）、二酸化ケイ素（ＳｉＯ2）、チタン酸ストロンチウム（ＳｒＴｉＯ3）、酸化ガリウム（Ｇａ2Ｏ3）、ニオブ酸リチウム（ＬｉＮｂＯ3）、チタン酸ジルコン酸鉛（ＰＺＴ）などを用いることができる。これらのフッ化物としては、例えば、フッ化カルシウム（ＣａＦ2）、フッ化マグネシウム（ＭｇＦ2）などを用いることができる。これらの中でも、酸化アルミニウム（Ａｌ2Ｏ3）、酸化マグネシウム（ＭｇＯ）、酸化ハフニウム（ＨｆＯ2）、および二酸化ケイ素（ＳｉＯ2）からなる群から選択されるいずれかを用いることが好ましい。 Examples of these oxides include aluminum oxide (Al 2 O 3 ), magnesium oxide (MgO), hafnium oxide (HfO 2 ), silicon dioxide (SiO 2 ), strontium titanate (SrTiO 3 ), and gallium oxide (SrTiO 3). Ga 2 O 3 ), lithium niobate (LiNbO 3 ), lead zirconate titanate (PZT) and the like can be used. As these fluorides, for example, calcium fluoride (CaF 2 ), magnesium fluoride (MgF 2 ) and the like can be used. Among these, it is preferable to use any one selected from the group consisting of aluminum oxide (Al 2 O 3 ), magnesium oxide (MgO), hafnium oxide (HfO 2 ), and silicon dioxide (SiO 2 ).
　第一の絶縁層２は、基板層１と、吸着層３との間で、ホールやキャリアの拡散を防止するために設ける。一方で、絶縁しすぎると、高い移動度を達成できなくなったり、半導体として使用できない場合がある。よって、第一の絶縁層の厚みは、４～１２ｎｍであることが好ましい。より好ましくは、６～１０ｎｍである。また、製造時の取り扱いやすさや、膜質の調整、基板層１との相性などから、特に、酸化アルミニウムを用いることが好ましく、厚さは８ｎｍ程度とすることが特に好ましい。これらの厚みは、透過型電子顕微鏡（ＴＥＭ）により測定することができる。 The first insulating layer 2 is provided between the substrate layer 1 and the adsorption layer 3 in order to prevent the diffusion of holes and carriers. On the other hand, if it is too insulated, it may not be possible to achieve high mobility or it may not be usable as a semiconductor. Therefore, the thickness of the first insulating layer is preferably 4 to 12 nm. More preferably, it is 6 to 10 nm. Further, from the viewpoint of ease of handling during manufacturing, adjustment of film quality, compatibility with the substrate layer 1, etc., it is particularly preferable to use aluminum oxide, and it is particularly preferable that the thickness is about 8 nm. These thicknesses can be measured with a transmission electron microscope (TEM).
［吸着層３］
　多層膜構造体１０（１０１）は、吸着層３を有する。吸着層３は、第一の絶縁層２の上に、第一の絶縁層２と接するように配置される。吸着層３は、二酸化窒素（ＮＯ2）、一酸化窒素（ＮＯ）、二酸化硫黄（ＳＯ2）、およびオゾン（Ｏ3）からなる群から選択されるいずれかの気体分子が吸着した層である。気体分子としては、前述のように、ＮＯ2、ＮＯ、ＳＯ2、およびＯ3からなる群から選択されるいずれかの気体分子を含むものを用いることができる。特に、ＮＯ2が吸着したものであることが好ましい。 [Adsorption layer 3]
The multilayer film structure 10 (101) has an adsorption layer 3. The adsorption layer 3 is arranged on the first insulating layer 2 so as to be in contact with the first insulating layer 2. The adsorption layer 3 is a layer on which any gas molecule selected from the group consisting of nitrogen dioxide (NO 2 ), nitric oxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ) is adsorbed. .. As the gas molecule, as described above, a gas molecule containing any gas molecule selected from the group consisting of NO 2 , NO, SO 2 , and O 3 can be used. In particular, it is preferable that NO 2 is adsorbed.
［第二の絶縁層４］
　多層膜構造体１０（１０１）は、第二の絶縁層４を有する。第二の絶縁層４は、吸着層３の上に、吸着層３と接するように配置される。第二の絶縁層４は、第一の絶縁層２と同様の材質を用いることができる。 [Second insulating layer 4]
The multilayer film structure 10 (101) has a second insulating layer 4. The second insulating layer 4 is arranged on the adsorption layer 3 so as to be in contact with the adsorption layer 3. As the second insulating layer 4, the same material as that of the first insulating layer 2 can be used.
　また、第二の絶縁層４の厚みは、４～１００ｎｍであることが好ましい。第二の絶縁層４の厚みの上限は、５０ｎｍ以下や、２０ｎｍ以下、１２ｎｍ以下、１０ｎｍ以下としてもよい。また、第二の絶縁層４の厚みの下限は６ｎｍ以上としてもよい。 Further, the thickness of the second insulating layer 4 is preferably 4 to 100 nm. The upper limit of the thickness of the second insulating layer 4 may be 50 nm or less, 20 nm or less, 12 nm or less, 10 nm or less. Further, the lower limit of the thickness of the second insulating layer 4 may be 6 nm or more.
［ゲート電極５］
　多層膜構造体１０（１０１）は、ゲート電極５を有する。ゲート電極５は、第二の絶縁層４の上に、第二の絶縁層４と接するように配置される。ゲート電極は、金属層であることが好ましい。金属層は、金（Ａｕ）や、金とチタンの積層膜（下層から順にＴｉ／Ａｕ）、金とチタンとアルミニウムの積層膜（下層から順にＡｌ／Ｔｉ／Ａｕ）などを用いることができる。 [Gate electrode 5]
The multilayer film structure 10 (101) has a gate electrode 5. The gate electrode 5 is arranged on the second insulating layer 4 so as to be in contact with the second insulating layer 4. The gate electrode is preferably a metal layer. As the metal layer, gold (Au), a laminated film of gold and titanium (Ti / Au in order from the lower layer), a laminated film of gold, titanium and aluminum (Al / Ti / Au in order from the lower layer) and the like can be used.
　多層膜構造体１０２（図３参照）のように、ソース電極８やドレイン電極９などの他の構造を有するものとすることができる。 Like the multilayer film structure 102 (see FIG. 3), it can have other structures such as a source electrode 8 and a drain electrode 9.
　多層膜構造体１０（１０１、１０２）は、電気伝導を用いる素子である電子素子などに用いることができる。例えば、トランジスタや、ダイオード、ＭＥＭＳなどに用いることができる。 The multilayer film structure 10 (101, 102) can be used for an electronic element or the like which is an element using electric conduction. For example, it can be used for transistors, diodes, MEMS and the like.
［製造方法のフロー］
　図３は、本発明の多層膜構造体の製造工程の一例を説明するための概要図である。多層膜構造体１０２は、工程１～工程６により製造することができる。
図３（ａ）工程１：まず、基板層１を製造する。例えば、ダイヤモンド結晶の基板層は、ＣＶＤ装置で成長させることができる。
図３（ｂ）工程２：次に、基板層１に水素吸着層１２を設ける。基板層１に水素プラズマを照射することで水素吸着層１２を形成することができる。
図３（ｃ）工程３：次に、基板層１の一端にソース電極８を設け、ソース電８と離隔させて他端にドレイン電極９を設ける。
図３（ｄ）工程４：次に、基板層１の水素吸着層１２に接するように、ソース電極８とドレイン電極９との間に第一の絶縁層２を設ける。第一の絶縁層２は、酸化アルミニウム（Ａｌ2Ｏ3）などの材質を堆積させる第一の堆積工程により設けることができる。
図３（ｅ）工程５：次に、第一の絶縁層２の上に、二酸化窒素（ＮＯ2）、一酸化窒素（ＮＯ）、二酸化硫黄（ＳＯ2）、およびオゾン（Ｏ3）からなる群から選択されるいずれかの気体分子を接触させて吸着層３を形成する形成工程を行う。さらに、吸着層３の上に、第二の絶縁層４を形成する部材を堆積させる第二の堆積工程を行う。
図３（ｆ）工程６：そして、第二の絶縁層４の上に、ゲート電極５を設けることで、多層膜構造体１０２を得ることができる。 [Manufacturing method flow]
FIG. 3 is a schematic diagram for explaining an example of a manufacturing process of the multilayer film structure of the present invention. The multilayer film structure 102 can be manufactured by steps 1 to 6.
FIG. 3A Step 1: First, the substrate layer 1 is manufactured. For example, the substrate layer of diamond crystals can be grown in a CVD apparatus.
FIG. 3B Step 2: Next, the hydrogen adsorption layer 12 is provided on the substrate layer 1. The hydrogen adsorption layer 12 can be formed by irradiating the substrate layer 1 with hydrogen plasma.
FIG. 3 (c) Step 3: Next, a source electrode 8 is provided at one end of the substrate layer 1, and a drain electrode 9 is provided at the other end of the substrate layer 1 so as to be separated from the source electric power 8.
FIG. 3D Step 4: Next, the first insulating layer 2 is provided between the source electrode 8 and the drain electrode 9 so as to be in contact with the hydrogen adsorption layer 12 of the substrate layer 1. The first insulating layer 2 can be provided by the first deposition step of depositing a material such as aluminum oxide (Al 2 O 3 ).
FIG. 3 (e) Step 5: Next, on the first insulating layer 2, it is composed of nitrogen dioxide (NO 2 ), nitric oxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ). A forming step is performed in which any gas molecule selected from the group is brought into contact with each other to form the adsorption layer 3. Further, a second deposition step of depositing a member forming the second insulating layer 4 on the adsorption layer 3 is performed.
FIG. 3 (f) Step 6: Then, by providing the gate electrode 5 on the second insulating layer 4, the multilayer film structure 102 can be obtained.
［水素吸着層形成工程］
　水素吸着層形成工程は、バンドギャップが３．０エレクトロンボルト以上の基板層１の表面に、水素吸着層を形成する工程である。水素吸着層の形成は、例えば、基板層１に水素プラズマを照射することで形成することができる。 [Hydrogen adsorption layer forming step]
The hydrogen adsorption layer forming step is a step of forming a hydrogen adsorption layer on the surface of the substrate layer 1 having a band gap of 3.0 electron volts or more. The hydrogen adsorption layer can be formed, for example, by irradiating the substrate layer 1 with hydrogen plasma.
［第一の堆積工程］
　第一の堆積工程は、第一の絶縁層を形成する部材を堆積させる第一の堆積工程であることが好ましい。第一の堆積工程は、酸化アルミニウム（Ａｌ2Ｏ3）を堆積させるものであり、試料温度は５０～３００℃で堆積せるものであることが好ましい。温度は、１００～２５０℃としてもよい。 [First deposition process]
The first deposition step is preferably the first deposition step of depositing the member forming the first insulating layer. The first deposition step is to deposit aluminum oxide (Al 2 O 3 ), and it is preferable that the sample temperature is 50 to 300 ° C. The temperature may be 100 to 250 ° C.
［形成工程］
　形成工程は、第一の絶縁層の表面に、二酸化窒素（ＮＯ2）、一酸化窒素（ＮＯ）、二酸化硫黄（ＳＯ2）、およびオゾン（Ｏ3）からなる群から選択されるいずれかの気体分子を接触させて吸着層を形成する形成工程であることが好ましい。形成工程は、気体分子を吸着させるものであり、気体分子ガスの濃度が０．２％以上であることが好ましい。気体分子の供給時間は３～２０分であることが好ましい。また、真空条件で行う場合、真空度は６．６７ｋＰａ～２６．７ｋＰａ（５０～２００ｔｏｒｒ）であることが好ましい。真空度は、特に、１４．７ｋＰａ～１８．７ｋＰａ（１１０～１４０ｔｏｒｒ）であることが好ましい。また、気体分子を吸着させたとき、安定したものとするために、試料温度は５０～２００℃で行うことが好ましい。 [Formation process]
The forming step is selected from the group consisting of nitrogen dioxide (NO 2 ), nitric oxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ) on the surface of the first insulating layer. It is preferable that the step is a forming step in which gas molecules are brought into contact with each other to form an adsorption layer. The forming step is for adsorbing gas molecules, and the concentration of the gas molecular gas is preferably 0.2% or more. The supply time of gas molecules is preferably 3 to 20 minutes. Further, in the case of performing under vacuum conditions, the degree of vacuum is preferably 6.67 kPa to 26.7 kPa (50 to 200 torr). The degree of vacuum is particularly preferably 14.7 kPa to 18.7 kPa (110 to 140 torr). Further, the sample temperature is preferably 50 to 200 ° C. in order to stabilize the gas molecules when they are adsorbed.
［第二の堆積工程］
　第二の堆積工程は、吸着層の表面に、第二の絶縁層を形成する部材を堆積させるものである。第二の堆積工程は、酸化アルミニウム（Ａｌ2Ｏ3）を堆積させるものであり、試料温度は５０～２００℃で堆積させるものであることが好ましい。 [Second deposition process]
The second deposition step is to deposit a member forming the second insulating layer on the surface of the adsorption layer. The second deposition step is for depositing aluminum oxide (Al 2 O 3 ), and it is preferable that the sample temperature is 50 to 200 ° C.
　これらの水素吸着層形成工程、第一の堆積工程、形成工程、および第二の堆積工程は、同一の処理槽内で行われ、その雰囲気が、制御された雰囲気であることが好ましい。雰囲気の制御としては、窒素置換したものや、真空などとすることができる。従来、堆積工程では大気中で行うことが好ましいと考えられていたが、本発明では、窒素置換や真空のまま行うことができる。このため、水素吸着層形成工程を行った処理槽と同一の槽内で、そのあとの堆積工程や形成工程等を行うことができ、製造工程の管理が行いやすく、優れた品質のものを安定して製造することができる。 It is preferable that these hydrogen adsorption layer forming steps, the first deposition step, the forming step, and the second deposition step are performed in the same treatment tank, and the atmosphere thereof is a controlled atmosphere. The atmosphere can be controlled by nitrogen substitution, vacuum, or the like. Conventionally, it has been considered preferable to carry out the deposition step in the atmosphere, but in the present invention, it can be carried out with nitrogen substitution or vacuum. Therefore, in the same tank as the treatment tank in which the hydrogen adsorption layer forming step was performed, the subsequent deposition step, formation step, etc. can be performed, the manufacturing process can be easily managed, and the one with excellent quality is stable. Can be manufactured.
　以下、実施例により本発明を更に詳細に説明するが、本発明は、その要旨を変更しない限り以下の実施例に限定されるものではない。 Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless the gist thereof is changed.
［実施例１］
　以下の工程で、図３の多層膜構造体１０２に相当する多層膜構造体を作製する例にて説明する。
（１）基板層１として、アダマンド並木精密宝石株式会社製のＫｅｎｚａｎ　ｄｉａｍｏｎｄ（登録商標）を用いた。
（２）基板層１に、マイクロ波プラズマＣＶＤ装置のリアクター内で水素プラズマ（Ｈで表す）を照射することにより、水素吸着層１２を形成した。マイクロ波の周波数２．４５ＧＨｚ、出力７５０Ｗ、反応圧力５０Ｔｏｒｒ（６．６７ｋＰａ）、水素の供給量３００ｃｃｍで１０分間おくことで水素吸着層１２を生成した。
（３）次に、ソース電極８と、ドレイン電極９を真空蒸着により形成した。
（４）次に、試料を、真空中で、原子層堆積（ＡＬＤ）法により、トリメチルアルミニウム、Ｈ2Ｏを交互に供給し、酸化アルミニウム層（Ａｌ2Ｏ3膜）を、第一の絶縁層２として堆積した。
（５）次に、２％の濃度のＮＯ2を供給しＮＯ2吸着層３を形成した。
（６）次に、再びＡＬＤ法を用いて酸化アルミニウム層（Ａｌ2Ｏ3膜）を、第二の絶縁層４として堆積した。
（７）最後に、ゲート電極層５となるＡｕ膜を蒸着する。 [Example 1]
An example of producing a multilayer film structure corresponding to the multilayer film structure 102 of FIG. 3 will be described in the following steps.
(1) As the substrate layer 1, Kenzan diamond (registered trademark) manufactured by Adamant Namiki Precision Jewel Co., Ltd. was used.
(2) The substrate layer 1 was irradiated with hydrogen plasma (represented by H) in the reactor of the microwave plasma CVD apparatus to form the hydrogen adsorption layer 12. The hydrogen adsorption layer 12 was formed by leaving the microwave at a frequency of 2.45 GHz, an output of 750 W, a reaction pressure of 50 Torr (6.67 kPa), and a hydrogen supply amount of 300 cm for 10 minutes.
(3) Next, the source electrode 8 and the drain electrode 9 were formed by vacuum deposition.
(4) Next, the sample is supplied with trimethylaluminum and H 2 O alternately in vacuum by the atomic layer deposition (ALD) method, and the aluminum oxide layer (Al 2 O 3 film) is first insulated. It was deposited as layer 2.
(5) Next, NO 2 having a concentration of 2% was supplied to form the NO 2 adsorption layer 3.
(6) Next, the aluminum oxide layer (Al 2 O 3 film) was deposited again as the second insulating layer 4 by using the ALD method again.
(7) Finally, an Au film to be the gate electrode layer 5 is deposited.
　実施例１に準じる製造例の概要を図６に示す。図６の多層膜構造体の説明について、「Ａｌ2Ｏ3－８ｎｍ＠２３０℃」と表記する場合、２３０℃で酸化アルミニウムの層を８ｎｍ堆積させたことを意味する。また、「ＮＯ2＠８０℃」は、８０℃でＮＯ2ガスを吸着させたことを意味する。また、「Ａｌ2Ｏ3－８ｎｍ＠８０℃」は、８０℃で酸化アルミニウムの層を８ｎｍ堆積させたことを意味する。 FIG. 6 shows an outline of a production example according to Example 1. Regarding the description of the multilayer film structure of FIG. 6, when it is described as "Al 2 O 3-8 nm @ 230 ° C.", it means that a layer of aluminum oxide is deposited at 230 ° C. by 8 nm. Further, "NO 2 @ 80 ° C." means that the NO 2 gas was adsorbed at 80 ° C. Further, "Al 2 O 3-8 nm @ 80 ° C." means that a layer of aluminum oxide was deposited at 80 ° C. by 8 nm.
　図７、８は、製造した試料のシート抵抗（ＳｈｅｅｔＲｅｓｉｓｔａｎｃｅ（ｋΩ／ｓｑ．））や、ドレイン電圧（出力電圧（ＶDS（Ｖ））に対するドレイン電流（（ＩDS（ｍＡ／ｍｍ））によりゲート電圧依存性を評価した結果を示す。これらの測定は、ＫＥＹＳＩＧＨＴ　ＴＥＣＨＮＯＬＯＧＩＥＳ社の「Ｂ１５０５Ａ　パワー・デバイス・アナライザ／カーブトレーサ」を用いて行った。 FIGS. 7 and 8 show gates based on the sheet resistance (Sheet Resistance (kΩ / sq.)) Of the manufactured sample and the drain current (( IDS (mA / mm)) with respect to the drain voltage (output voltage (V DS (V))). The results of evaluating the voltage dependence are shown. These measurements were performed using a "B1505A power device analyzer / curve tracer" manufactured by KEYSIGHT TECHNOLOGIES.
　図７は、第一の絶縁層として酸化アルミニウム層の厚みや処理温度を検討した結果である。なお、図７、８の検討において、変更した条件以外は、図６に示す構成として評価した。第一の絶縁層は、特に８ｎｍのとき、最もシート抵抗が低いものとなった。 FIG. 7 shows the results of examining the thickness and treatment temperature of the aluminum oxide layer as the first insulating layer. In the examination of FIGS. 7 and 8, the configurations shown in FIG. 6 were evaluated except for the changed conditions. The first insulating layer had the lowest sheet resistance, especially at 8 nm.
　図８は、ＮＯ2吸着層を形成する形成工程の処理温度を検討した結果である。ＮＯ2吸着層を形成する温度は、８０℃程度としたとき、よりシート抵抗が低いものとなった。なお、図８において、グラフ中の（８０℃，８０℃）や、（２３０℃，８０℃）、（２３０℃，２３０℃）の記載は、グラフ内の各測定点の試験条件に関するものである。カッコ内の左側が、第一の酸化アルミニウム層（第一Ａｌ2Ｏ3）堆積時の試料温度であり、カッコ内の右側が、第二の酸化アルミニウム層（第二Ａｌ2Ｏ3）堆積時の試料温度である。例えば、（８０℃，８０℃）は、第一の酸化アルミニウム層堆積時の試料温度が８０℃であり、第二の酸化アルミニウム層堆積時の試料温度が８０℃である。 FIG. 8 shows the results of examining the treatment temperature in the forming step of forming the NO 2 adsorption layer. When the temperature at which the NO 2 adsorption layer was formed was about 80 ° C., the sheet resistance became lower. In FIG. 8, the description of (80 ° C., 80 ° C.), (230 ° C., 80 ° C.), and (230 ° C., 230 ° C.) in the graph relates to the test conditions of each measurement point in the graph. .. The left side in parentheses is the sample temperature when the first aluminum oxide layer (first Al 2 O 3 ) is deposited, and the right side in parentheses is the sample temperature when the second aluminum oxide layer (second Al 2 O 3 ) is deposited. Sample temperature. For example, in (80 ° C., 80 ° C.), the sample temperature at the time of depositing the first aluminum oxide layer is 80 ° C., and the sample temperature at the time of depositing the second aluminum oxide layer is 80 ° C.
　図９は、図９左側に示す構成の多層膜構造体のゲート電圧依存性を評価した結果である。特に、第一の絶縁層の堆積条件として、温度（Ｘ℃）を、８０℃、２３０℃、３３０℃で製造した例である。これらの製造温度で製造した多層膜構造のＦＥＴの最大ドレイン電流を測定した結果を、図９右に示す。 FIG. 9 is a result of evaluating the gate voltage dependence of the multilayer film structure having the configuration shown on the left side of FIG. 9. In particular, it is an example in which the temperature (X ° C.) is 80 ° C., 230 ° C., and 330 ° C. as the deposition condition of the first insulating layer. The results of measuring the maximum drain current of the FET having a multilayer structure manufactured at these manufacturing temperatures are shown on the right side of FIG.
　本発明の多層膜構造体は、トランジスタやダイオードなどの電子素子に利用することができ、産業上有用である。 The multilayer film structure of the present invention can be used for electronic elements such as transistors and diodes, and is industrially useful.
　１　基板層
　１０、１０１、１０２、２０、２０１　多層膜構造体
　１２　水素吸着層
　２　第一の絶縁層
　３　吸着層
　４　第二の絶縁層
　５　ゲート電極
　８　ソース電極
　９　ドレイン電極 1 Substrate layer 10, 101, 102, 20, 201 Multilayer membrane structure 12 Hydrogen adsorption layer 2 First insulation layer 3 Adsorption layer 4 Second insulation layer 5 Gate electrode 8 Source electrode 9 Drain electrode

Claims (8)

  1. 　バンドギャップが、３．０エレクトロンボルト以上の基板層と、
    　前記基板層の上に配置された第一の絶縁層と、
    　前記第一の絶縁層の上に配置された、二酸化窒素（ＮＯ2）、一酸化窒素（ＮＯ）、二酸化硫黄（ＳＯ2）、およびオゾン（Ｏ3）からなる群から選択されるいずれかの気体分子の吸着層と、
    　前記吸着層の上に配置された第二の絶縁層と、
    　前記第二の絶縁層の上に配置されたゲート電極層と、を有する、多層膜構造体。     A substrate layer with a bandgap of 3.0 electron volts or more,
    The first insulating layer arranged on the substrate layer and
    Any one selected from the group consisting of nitrogen dioxide (NO 2 ), nitric oxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ) arranged on the first insulating layer. Adsorption layer of gas molecules and
    A second insulating layer arranged on the adsorption layer and
    A multilayer film structure having a gate electrode layer arranged on the second insulating layer.
  2. 　前記基板層が、窒化ガリウム（ＧａＮ）、炭化シリコン（ＳｉＣ）、酸化ガリウム（Ｇａ2Ｏ3）、およびダイヤモンドからなる群から選択されるいずれかの結晶を含み、
    　前記第一の絶縁層および前記第二の絶縁層が、酸化物またはフッ化物の層であり、
    　前記ゲート電極層が、金属の層である、請求項１に記載の多層膜構造体。     The substrate layer comprises any crystal selected from the group consisting of gallium nitride (GaN), silicon carbide (SiC), gallium oxide (Ga 2 O 3 ), and diamond.
    The first insulating layer and the second insulating layer are layers of oxides or fluorides.
    The multilayer film structure according to claim 1, wherein the gate electrode layer is a metal layer.
  3. 　前記基板層が、水素吸着層を有するダイヤモンド結晶の層であり、
    　前記第一の絶縁層が、厚み４～１２ｎｍの酸化アルミニウム（Ａｌ2Ｏ3）の層であり、
    　前記吸着層が、二酸化窒素（ＮＯ2）吸着層であり、
    　前記第二の絶縁層が、厚み４～１００ｎｍの酸化アルミニウム（Ａｌ2Ｏ3）の層であり、
    　前記ゲート電極が、金属の層である、請求項１に記載の多層膜構造体。     The substrate layer is a layer of diamond crystals having a hydrogen adsorption layer.
    The first insulating layer is a layer of aluminum oxide (Al 2 O 3 ) having a thickness of 4 to 12 nm.
    The adsorption layer is a nitrogen dioxide (NO 2 ) adsorption layer.
    The second insulating layer is a layer of aluminum oxide (Al 2 O 3 ) having a thickness of 4 to 100 nm.
    The multilayer film structure according to claim 1, wherein the gate electrode is a metal layer.
  4. 　請求項１～３のいずれかに記載の多層膜構造体を含む、電子素子。 An electronic device including the multilayer film structure according to any one of claims 1 to 3.
  5. 　バンドギャップが、３．０エレクトロンボルト以上の基板層の表面に、制御された雰囲気下で、第一の絶縁層を形成する部材を堆積させる第一の堆積工程と、
    　前記第一の絶縁層の表面に、制御された雰囲気下で、二酸化窒素（ＮＯ2）、一酸化窒素（ＮＯ）、二酸化硫黄（ＳＯ2）、およびオゾン（Ｏ3）からなる群から選択されるいずれかの気体分子を接触させて吸着層を形成する形成工程と、
    　前記吸着層の表面に、制御された雰囲気下で、第二の絶縁層を形成する部材を堆積させる第二の堆積工程と、を有する、多層膜構造体の製造方法。     The first deposition step of depositing the member forming the first insulating layer on the surface of the substrate layer having a bandgap of 3.0 electron volts or more in a controlled atmosphere.
    The surface of the first insulating layer is selected from the group consisting of nitrogen dioxide (NO 2 ), nitric oxide (NO), sulfur dioxide (SO 2 ), and ozone (O 3 ) under a controlled atmosphere. A forming step of contacting any of the gas molecules to form an adsorption layer,
    A method for producing a multilayer film structure, comprising a second deposition step of depositing a member forming a second insulating layer on the surface of the adsorption layer under a controlled atmosphere.
  6. 　前記第一の堆積工程の前に、前記基板層の表面に、水素プラズマを照射することで、水素吸着層を形成させる水素吸着層形成工程を有する、請求項５に記載の製造方法。 The production method according to claim 5, further comprising a hydrogen adsorption layer forming step of irradiating the surface of the substrate layer with hydrogen plasma to form a hydrogen adsorption layer before the first deposition step.
  7. 　前記水素吸着形成工程、前記第一の堆積工程、前記形成工程、および前記第二の堆積工程が、同一の処理槽内で行われ、前記雰囲気が、真空または窒素置換された雰囲気である、請求項６に記載の製造方法。 Claimed that the hydrogen adsorption forming step, the first deposition step, the forming step, and the second deposition step are performed in the same treatment tank, and the atmosphere is a vacuum or nitrogen-substituted atmosphere. Item 6. The manufacturing method according to Item 6.
  8. 　前記第一の堆積工程が、酸化アルミニウム（Ａｌ2Ｏ3）を堆積させるものであり、試料温度は５０～３００℃で堆積させるものであり、
    　前記形成工程が、二酸化窒素（ＮＯ2）を吸着させるものであり、前記形成工程において、ＮＯ2ガスの濃度が０．２％以上であり、供給時間が３～２０分であり、真空度は６．６７ｋＰａ～２６．７ｋＰａであり、かつ、試料温度は５０～２００℃で吸着させるものであり、
    　前記第二の堆積工程が、酸化アルミニウム（Ａｌ2Ｏ3）を堆積させるものであり、試料温度は５０～２００℃で堆積させるものである、請求項５～７のいずれかに記載の製造方法。     The first deposition step is for depositing aluminum oxide (Al 2 O 3 ), and the sample temperature is 50 to 300 ° C.
    The forming step adsorbs nitrogen dioxide (NO 2 ). In the forming step, the concentration of NO 2 gas is 0.2% or more, the supply time is 3 to 20 minutes, and the degree of vacuum is high. It is 6.67 kPa to 26.7 kPa, and the sample temperature is 50 to 200 ° C. for adsorption.
    The production method according to any one of claims 5 to 7, wherein the second deposition step deposits aluminum oxide (Al 2 O 3 ) at a sample temperature of 50 to 200 ° C. ..
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