CN113871465A - Diamond field effect transistor and preparation method thereof - Google Patents
Diamond field effect transistor and preparation method thereof Download PDFInfo
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- CN113871465A CN113871465A CN202110994689.4A CN202110994689A CN113871465A CN 113871465 A CN113871465 A CN 113871465A CN 202110994689 A CN202110994689 A CN 202110994689A CN 113871465 A CN113871465 A CN 113871465A
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- 229910003460 diamond Inorganic materials 0.000 title claims abstract description 110
- 239000010432 diamond Substances 0.000 title claims abstract description 110
- 238000002360 preparation method Methods 0.000 title abstract description 13
- 238000002353 field-effect transistor method Methods 0.000 title description 2
- 230000005669 field effect Effects 0.000 claims abstract description 43
- 239000010410 layer Substances 0.000 claims description 246
- 229910052751 metal Inorganic materials 0.000 claims description 151
- 239000002184 metal Substances 0.000 claims description 151
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 118
- 239000001257 hydrogen Substances 0.000 claims description 116
- 229910052739 hydrogen Inorganic materials 0.000 claims description 116
- 238000005530 etching Methods 0.000 claims description 72
- 239000000758 substrate Substances 0.000 claims description 33
- 238000000034 method Methods 0.000 claims description 23
- 238000000151 deposition Methods 0.000 claims description 18
- 238000001312 dry etching Methods 0.000 claims description 13
- 238000001039 wet etching Methods 0.000 claims description 12
- 229920002120 photoresistant polymer Polymers 0.000 claims description 11
- 238000000137 annealing Methods 0.000 claims description 10
- 230000008021 deposition Effects 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 7
- 238000012546 transfer Methods 0.000 claims description 6
- 239000011248 coating agent Substances 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 5
- 239000013078 crystal Substances 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 238000005275 alloying Methods 0.000 claims description 3
- 150000002739 metals Chemical class 0.000 claims description 3
- 238000009832 plasma treatment Methods 0.000 claims description 3
- 239000002356 single layer Substances 0.000 claims description 3
- 238000001883 metal evaporation Methods 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 6
- 230000009286 beneficial effect Effects 0.000 description 4
- 238000001704 evaporation Methods 0.000 description 2
- 239000004047 hole gas Substances 0.000 description 2
- 229940077844 iodine / potassium iodide Drugs 0.000 description 2
- 238000001259 photo etching Methods 0.000 description 2
- 239000002156 adsorbate Substances 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 238000000231 atomic layer deposition Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/401—Multistep manufacturing processes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/41—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
- H01L29/423—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions not carrying the current to be rectified, amplified or switched
- H01L29/42312—Gate electrodes for field effect devices
- H01L29/42316—Gate electrodes for field effect devices for field-effect transistors
- H01L29/4232—Gate electrodes for field effect devices for field-effect transistors with insulated gate
- H01L29/42356—Disposition, e.g. buried gate electrode
- H01L29/4236—Disposition, e.g. buried gate electrode within a trench, e.g. trench gate electrode, groove gate electrode
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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/45—Ohmic electrodes
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- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/49—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET
- H01L29/51—Insulating materials associated therewith
- H01L29/518—Insulating materials associated therewith the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/66015—Multistep manufacturing processes of devices having a semiconductor body comprising semiconducting carbon, e.g. diamond, diamond-like carbon, graphene
- H01L29/66037—Multistep manufacturing processes of devices having a semiconductor body comprising semiconducting carbon, e.g. diamond, diamond-like carbon, graphene 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
- H01L29/66045—Field-effect transistors
Abstract
The invention provides a diamond field effect transistor and a preparation method thereof, belonging to the technical field of diamond field effect transistor devices. The diamond field effect transistor and the preparation method provided by the invention have the technical effects of reducing the interface state density of the diamond field effect transistor and improving the direct current and radio frequency performance of a device.
Description
Technical Field
The invention belongs to the technical field of diamond field effect transistor devices, and particularly relates to a diamond field effect transistor and a preparation method thereof.
Background
At present, the research of diamond field effect transistors is mainly based on two-dimensional hole gas conduction of a hydrogen terminal structure, and when hydrogen terminal diamond is exposed in the air for a plurality of hours, certain charged ions (such as HCO) appear on the surface3+，OH-，HCO3-，NO3And the like), due to the negative electron affinity of the hydrogen terminal diamond, electrons on the surface of the adsorbate are transferred into the adsorption layer, so that a layer of two-dimensional hole gas is generated on the surface of the diamond to form a p-type conduction channel. Current carrier mobility for hydrogen terminated diamond is generally<200cm2V.s, sheet resistance 10,000 omega, and carrier surface density 1012-1014/cm2The direct current and radio frequency performance of the diamond field effect transistor are severely restricted by lower mobility and higher sheet resistance. Theoretical analysis shows that ionized impurity scattering introduced by the interface state between the hydrogen terminal diamond and the dielectric layer is one of the main factors for limiting the mobility, and the density of the interface state between the hydrogen terminal diamond and the dielectric layer is usually 10 at present12/cm2The mobility can reach 1000cm2V.s; interface state density is reduced to 1010/cm2The mobility can reach 3000cm2V.s; therefore, the problem of the interface between diamond and a medium is solved, and the reduction of the interface state density is the key for realizing the high-performance diamond field effect transistor.
Disclosure of Invention
The invention aims to provide a diamond field effect transistor and a preparation method thereof, and aims to solve the technical problem of high interface state density of the diamond field effect transistor.
In order to achieve the purpose, the invention adopts the technical scheme that: the diamond field effect transistor comprises a diamond substrate, a hydrogen terminal, an ohmic contact metal layer, a dielectric layer, an h-BN dielectric layer and a gate metal layer, wherein the hydrogen terminal is formed on the upper surface of the diamond substrate; the ohmic contact metal layer is formed on the upper surface of the hydrogen terminal and comprises two electrodes arranged at intervals, and at least part of the hydrogen terminal covered by the ohmic contact metal layer and the hydrogen terminal between the two electrodes are conductive channel regions; the dielectric layer is formed on the ohmic contact metal layer and the hydrogen terminal, and an etching groove exposing the hydrogen terminal is formed in the region of the dielectric layer corresponding to the conductive channel region; an h-BN dielectric layer is formed on the dielectric layer and in the etching groove, a gate metal groove is arranged in the region of the h-BN dielectric layer corresponding to the etching groove, and the hydrogen terminal is not exposed by the gate metal groove; and the gate metal layer is formed in the gate metal groove and on the h-BN dielectric layer adjacent to the gate metal groove.
In a possible implementation manner, photoresist is coated on the upper surface of the dielectric layer, the dielectric layer is etched through an etching process to form the etching groove, and annealing treatment is performed in a hydrogen environment after etching.
The diamond field effect transistor provided by the invention has the beneficial effects that: compared with the prior art, the diamond field effect transistor comprises a diamond substrate, a hydrogen terminal, an ohmic contact metal layer, a dielectric layer, an h-BN dielectric layer and a gate metal layer, wherein the hydrogen terminal is formed on the upper surface of the diamond substrate, the ohmic contact metal layer is formed on the upper surface of the hydrogen terminal and comprises two electrodes which are arranged at intervals, at least part of the hydrogen terminal covered by the ohmic contact metal layer and the hydrogen terminal between the two electrodes are a conductive channel region, the dielectric layer is formed on the ohmic contact metal layer and the hydrogen terminal, an etching groove for exposing the hydrogen terminal is formed in the region of the dielectric layer corresponding to the conductive channel region, the h-BN dielectric layer is formed on the dielectric layer and in the etching groove, a gate metal groove is formed in the region of the h-BN dielectric layer corresponding to the etching groove, the gate metal groove does not expose the hydrogen terminal, the gate metal layer is formed in the gate metal groove and on the h-BN dielectric layer adjacent to the gate metal groove, the technical problem that the interface state density of the diamond field effect transistor is high is solved, and the technical effects of reducing the interface state density of the diamond field effect transistor and improving the direct current and radio frequency performance of a device are achieved.
The invention also provides a preparation method of the diamond field effect transistor, which comprises the following steps:
forming a hydrogen termination on a diamond substrate;
forming an ohmic contact metal layer on the hydrogen terminal diamond, wherein the ohmic contact metal layer comprises two electrodes which are arranged at intervals, and at least part of the hydrogen terminal covered by the ohmic contact metal layer and the hydrogen terminal between the two electrodes are conductive channel regions;
forming a dielectric layer on the ohmic contact metal layer and the hydrogen terminal, and forming an etching groove exposing the hydrogen terminal in a region of the dielectric layer corresponding to the conductive channel region;
forming an h-BN dielectric layer on the dielectric layer and in the etching groove, wherein a gate metal groove is arranged in the region of the h-BN dielectric layer corresponding to the etching groove, and the hydrogen terminal is not exposed by the gate metal groove;
and forming a gate metal layer in the gate metal groove and on the h-BN dielectric layer adjacent to the gate metal groove.
In one possible implementation, forming a hydrogen termination on a diamond substrate includes:
and preparing a sacrificial layer on the upper surface of the hydrogen terminal diamond in a metal evaporation mode, wherein the metal of the sacrificial layer is Au.
In one possible implementation, forming an ohmic contact metal layer on the hydrogen-terminated diamond includes:
depositing ohmic contact metal on the upper surface of the hydrogen terminal diamond in a deposition mode to form an ohmic contact metal layer;
and removing the sacrificial layer on the hydrogen terminal diamond by a wet etching mode or a dry etching mode.
In one possible implementation manner, forming a dielectric layer on the ohmic contact metal layer and the hydrogen terminal, and forming an etching groove exposing the hydrogen terminal in a region of the dielectric layer corresponding to the conductive channel region, includes:
coating photoresist on the dielectric layer, etching the dielectric layer in an etching mode to form the etching groove, and annealing under the condition of hydrogen after etching;
the dielectric layer is a single-layer dielectric or a multi-layer dielectric, and the thickness of the dielectric layer is 1-500 nm;
the method for etching the dielectric layer by the etching method is dry etching or wet etching or combined etching of the dry etching and the wet etching.
In one possible implementation manner, forming an h-BN dielectric layer on the dielectric layer and the etching groove, and forming a gate metal layer in the gate metal groove and on the h-BN dielectric layer adjacent to the gate metal groove includes:
transferring an h-BN dielectric layer on the dielectric layer and in the etching groove in a dry transfer or wet transfer mode, wherein the h-BN dielectric layer is a layer of dielectric or a plurality of layers of dielectric;
and depositing gate metal in a deposition mode to form the gate metal layer, and stripping to form a gate.
In one possible implementation, the metal of the ohmic contact metal layer is at least one metal, or a plurality of metals that can be formed through an alloying process.
In one possible implementation, the diamond substrate is single crystal diamond or polycrystalline diamond, and the hydrogen termination is obtained by hydrogen plasma treatment and annealing treatment under hydrogen conditions or epitaxial growth under hydrogen conditions.
In a possible implementation manner, the shape of the gate metal layer is one or a combination of more of a straight gate, a T-shaped gate, a TT-shaped gate, a TTT-shaped gate, a U-shaped gate and a Y-shaped gate.
The preparation method of the diamond field effect transistor has the beneficial effects that: compared with the prior art, the preparation method of the diamond field effect transistor comprises the steps of forming a hydrogen terminal on a diamond substrate, forming an ohmic contact metal layer on the hydrogen terminal diamond, forming a dielectric layer on the ohmic contact metal layer and the hydrogen terminal, forming an etching groove on the dielectric layer, forming an h-BN dielectric layer on the dielectric layer and the etching groove, arranging a gate metal groove in the region of the h-BN dielectric layer corresponding to the etching groove, and forming a gate metal layer in the gate metal groove and on the h-BN dielectric layer adjacent to the gate metal groove. The diamond field effect transistor and the preparation method provided by the invention solve the technical problem of high interface state density of the diamond field effect transistor, and have the technical effects of reducing the interface state density of the diamond field effect transistor and improving the direct current and radio frequency performance of a device.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed for the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a diamond field effect transistor provided in an embodiment of the present invention;
fig. 2 is a flow chart of a method for manufacturing a diamond field effect transistor according to an embodiment of the present invention.
Description of reference numerals:
1. a diamond substrate; 2. a hydrogen termination; 3. a sacrificial layer; 4. an active region; 5. an ohmic contact metal layer; 6. a dielectric layer; 7. h-BN dielectric layer; 8. a gate metal layer; 9. etching a groove; 10. and a gate metal trench.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 1, a diamond field effect transistor according to the present invention will now be described. The diamond field effect transistor comprises a diamond substrate 1, a hydrogen terminal 2, an ohmic contact metal layer 5, a dielectric layer 6, an h-BN dielectric layer 7 and a gate metal layer 8, wherein the hydrogen terminal 2 is formed on the upper surface of the diamond substrate 1; the ohmic contact metal layer 5 is formed on the upper surface of the hydrogen terminal 2, the ohmic contact metal layer 5 comprises two electrodes which are arranged at intervals, and at least part of the hydrogen terminal 2 covered by the ohmic contact metal layer 5 and the hydrogen terminal 2 between the two electrodes are conductive channel regions; the dielectric layer 6 is formed on the ohmic contact metal layer 5 and the hydrogen terminal 2, and an etching groove 9 for exposing the hydrogen terminal is formed in the region of the dielectric layer 6 corresponding to the conductive channel region; the h-BN dielectric layer 7 is formed on the dielectric layer and in the etching groove 9, a gate metal groove 10 is arranged in the region of the h-BN dielectric layer 7 corresponding to the etching groove 9, and the hydrogen terminal 2 is not exposed out of the gate metal groove 10; the gate metal layer 8 is formed in the gate metal groove 10 and on the h-BN dielectric layer 7 adjacent to the gate metal groove 10.
The diamond field effect transistor provided by the invention has the beneficial effects that: compared with the prior art, the diamond field effect transistor comprises a diamond substrate 1, a hydrogen terminal 2, an ohmic contact metal layer 5, a dielectric layer 6, an h-BN dielectric layer 7 and a gate metal layer 8, wherein the hydrogen terminal 2 is formed on the upper surface of the diamond substrate 1; the ohmic contact metal layer 5 is formed on the upper surface of the hydrogen terminal 2, the ohmic contact metal layer 5 comprises two electrodes which are arranged at intervals, and at least part of the hydrogen terminal 2 covered by the ohmic contact metal layer 5 and the hydrogen terminal 2 between the two electrodes are conductive channel regions; the dielectric layer 6 is formed on the ohmic contact metal layer 5 and the hydrogen terminal 2, and an etching groove 9 for exposing the hydrogen terminal is formed in the region of the dielectric layer 6 corresponding to the conductive channel region; the h-BN dielectric layer 7 is formed on the dielectric layer and in the etching groove 9, a gate metal groove 10 is arranged in the region of the h-BN dielectric layer 7 corresponding to the etching groove 9, and the hydrogen terminal 2 is not exposed out of the gate metal groove 10; the gate metal layer 8 is formed in the gate metal groove 10 and on the h-BN dielectric layer 7 adjacent to the gate metal groove 10, so that the technical problem of high interface state density of the diamond field effect transistor is solved, and the technical effects of reducing the interface state density of the diamond field effect transistor and improving the direct current and radio frequency performance of a device are achieved.
In some embodiments, referring to fig. 1, a photoresist is coated on the upper surface of the dielectric layer 6, the dielectric layer 6 is etched by an etching process to form the etching trench 9, and annealing treatment is performed in a hydrogen atmosphere after etching.
Specifically, a sacrificial layer 3 is prepared on the hydrogen terminal 2 diamond, and an active region 4 is arranged in the middle of the sacrificial layer 3; the ohmic contact metal layer 5 is positioned on the diamond substrate 1 of the removed sacrificial layer 3 outside the active region 4; a dielectric layer 6 is located on the sacrificial layer 3 and on the ohmic contact metal layer 5 within the removed active region 4 on the diamond substrate 1. And coating photoresist on the sacrificial layer 3 and covering the sacrificial layer with an active region 4, wherein the active region 4 is a conductive channel region of the device, removing the sacrificial layer 3 outside the active region 4, and depositing an ohmic contact metal layer 5 in a deposition mode.
Referring to fig. 2, the present invention further provides a method for manufacturing a diamond field effect transistor, including:
forming a hydrogen termination 2 on a diamond substrate 1;
forming an ohmic contact metal layer 5 on the hydrogen terminal 2 diamond, wherein the ohmic contact metal layer 5 comprises two electrodes arranged at intervals, and at least part of the hydrogen terminal 2 covered by the ohmic contact metal layer 5 and the hydrogen terminal between the two electrodes are conductive channel regions;
forming a dielectric layer 6 on the ohmic contact metal layer 5 and the hydrogen terminal 2, and forming an etching groove 9 exposing the hydrogen terminal 2 in a region of the dielectric layer 6 corresponding to the conductive channel region;
forming an h-BN dielectric layer 7 on the dielectric layer 6 and in the etching groove 9, wherein a gate metal groove 10 is arranged in the region of the h-BN dielectric layer 7 corresponding to the etching groove 9, and the gate metal groove 10 is not exposed out of the hydrogen terminal 2;
and forming a gate metal layer 8 in the gate metal groove 10 and on the h-BN dielectric layer 7 adjacent to the gate metal groove 10.
The preparation method of the diamond field effect transistor has the beneficial effects that: compared with the prior art, the preparation method of the diamond field effect transistor comprises the steps of forming the hydrogen terminal 2 on the diamond substrate, forming the ohmic contact metal layer 5 on the diamond of the hydrogen terminal 2, forming the dielectric layer 6 on the ohmic contact metal layer 5 and the hydrogen terminal 2, forming the etching groove 9 on the dielectric layer 6, forming the h-BN dielectric layer 7 on the dielectric layer 6 and the etching groove 9, arranging the gate metal groove 10 in the area of the h-BN dielectric layer 7 corresponding to the etching groove 9, and forming the gate metal layer 8 in the gate metal groove 10 and on the h-BN dielectric layer 7 adjacent to the gate metal groove 10. The diamond field effect transistor and the preparation method provided by the invention solve the technical problem of high interface state density of the diamond field effect transistor, and have the technical effects of reducing the interface state density of the diamond field effect transistor and improving the direct current and radio frequency performance of a device.
Specifically, a sacrificial layer 3 is prepared on the hydrogen terminal 2 diamond, and an active region 4 is arranged in the middle of the sacrificial layer 3; the ohmic contact metal layer 5 is positioned on the diamond substrate 1 of the removed sacrificial layer 3 outside the active region 4; a dielectric layer 6 is located on the sacrificial layer 3 and on the ohmic contact metal layer 5 within the removed active region 4 on the diamond substrate 1. And coating photoresist on the sacrificial layer 3 and covering the sacrificial layer with an active region 4, wherein the active region 4 is a conductive channel region of the device, removing the sacrificial layer 3 outside the active region 4, and depositing an ohmic contact metal layer 5 in a deposition mode.
Taking a single crystal diamond substrate 1, and processing the surface of the single crystal diamond substrate 1 for 10 minutes by microwave plasma chemical vapor deposition equipment under the environment of hydrogen plasma and at the temperature of 850 ℃ to form the diamond substrate 1 with a hydrogen terminal 2.
In some embodiments, referring to fig. 2, forming a hydrogen termination 2 on a diamond substrate 1 includes:
and preparing a sacrificial layer on the upper surface of the diamond of the hydrogen terminal 2 by evaporating metal, wherein the metal of the sacrificial layer is Au.
The way of evaporating the metal can be realized by means of the prior art, and specifically, metal Au with the thickness of 30nm is evaporated to be used as the sacrificial layer 3.
Photoetching is carried out on a sacrificial layer 3 of a diamond substrate 1 of a hydrogen terminal 2, photoresist covers an active region 4, the active region 4 is a conducting channel region of a device, the photoresist is used as a mask, the sacrificial layer 3Au outside the active region 4 is removed through wet etching of iodine/potassium iodide solution, and the conducting channel of the diamond substrate 1 of the hydrogen terminal 2 is removed through oxygen plasma bombardment, so that mesa isolation is realized.
In some embodiments, referring to fig. 2, an ohmic contact metal layer 5 is formed on the hydrogen termination 2 diamond, comprising:
depositing ohmic contact metal on the upper surface of the diamond of the hydrogen terminal 2 by a deposition mode to form an ohmic contact metal layer 5;
and removing the sacrificial layer 3 on the diamond of the hydrogen terminal 2 by a wet etching mode or a dry etching mode.
Specifically, the sacrificial layer 3 located outside the active region 4 is removed by a wet etching method or a dry etching method, and the sacrificial layer 3 in the active region 4 is removed by a dry etching method. The deposition mode, the wet etching mode and the dry etching mode can be realized by adopting the prior art means.
In some embodiments, referring to fig. 2, forming a dielectric layer 6 on the ohmic contact metal layer 5 and the hydrogen terminal 2, and forming an etching trench 9 exposing the hydrogen terminal 2 in a region of the dielectric layer 6 corresponding to the conductive channel region, includes:
coating photoresist on the dielectric layer 6, etching the dielectric layer 6 in an etching mode to form the etching groove 9, and annealing under the condition of hydrogen after etching;
the dielectric layer 6 is a single-layer dielectric or a multi-layer dielectric, and the thickness of the dielectric layer 6 is 1-500 nm;
the method for etching the dielectric layer 6 by etching is dry etching or wet etching or combined etching of the dry etching and the wet etching.
Etching the sacrificial layer 3Au on the diamond substrate 1 by an iodine/potassium iodide solution and depositing SiO with a thickness of 60nm by an atomic layer deposition technique2A dielectric layer 6.
Photoetching a pattern with the length of 500nm on the dielectric layer 6 by using an electron beam, taking the photoresist as a mask, and leading the SiO in the region2And completely removing the dielectric layer 6 by dry etching, and annealing in a hydrogen atmosphere after etching to repair the hydrogen terminal 2 on the surface of the diamond substrate 1.
The pattern of the etching groove 9 is not limited in this embodiment, and the etching can be completed. Preferably a cube shaped recess.
In some embodiments, referring to fig. 2, forming an h-BN dielectric layer 7 on the dielectric layer 6 and the etching groove 9, and forming a gate metal layer 8 in the gate metal groove 10 and on the h-BN dielectric layer 7 adjacent to the gate metal groove 10 include:
transferring an h-BN dielectric layer 7 on the dielectric layer 6 and in the etching groove 9 in a dry transfer or wet transfer mode, wherein the h-BN dielectric layer 7 is a layer of dielectric or a plurality of layers of dielectric;
and depositing a gate metal by a deposition mode to form the gate metal layer 8, and stripping to form a gate.
Specifically, a grid with the length of 1 micron is photoetched, and grid metal Al/Au is deposited and stripped to form a grid.
In some embodiments, referring to fig. 2, the metal of the ohmic contact metal layer 5 is at least one metal, or a plurality of metals formed by an alloy process.
Preferably, the metal of the ohmic contact metal layer 5 is three kinds and formed by an alloying process, is Ti/Pt/Au, and is alloyed at a temperature of 700 c for 1 hour to form an ohmic contact.
In some embodiments, referring to fig. 2, the diamond substrate 1 is single crystal diamond or polycrystalline diamond, and the hydrogen termination 2 is obtained by hydrogen plasma treatment and annealing treatment under hydrogen conditions or epitaxial growth under hydrogen conditions.
In some embodiments, referring to fig. 2, the gate metal layer 8 has a shape of one or more of a straight gate, a T-shaped gate, a TT-shaped gate, a TTT-shaped gate, a U-shaped gate, and a Y-shaped gate. The gate metal layer 8 is formed in a gate metal groove 10 corresponding to the etched groove 9 on the h-BN dielectric layer 7.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A diamond field effect transistor, comprising:
a diamond substrate;
a hydrogen termination formed on an upper surface of the diamond substrate;
the ohmic contact metal layer is formed on the upper surface of the hydrogen terminal and comprises two electrodes which are arranged at intervals, and at least part of the hydrogen terminal covered by the ohmic contact metal layer and the hydrogen terminal between the two electrodes are conductive channel regions;
the dielectric layer is formed on the ohmic contact metal layer and the hydrogen terminal, and an etching groove exposing the hydrogen terminal is formed in the region of the dielectric layer corresponding to the conductive channel region;
the h-BN dielectric layer is formed on the dielectric layer and in the etching groove, a gate metal groove is arranged in the area of the h-BN dielectric layer corresponding to the etching groove, and the hydrogen terminal is not exposed by the gate metal groove;
and the gate metal layer is formed in the gate metal groove and on the h-BN dielectric layer adjacent to the gate metal groove.
2. The diamond field effect transistor according to claim 1, wherein a photoresist is coated on the upper surface of the dielectric layer, the dielectric layer is etched by an etching process to form the etching groove, and annealing treatment is performed in a hydrogen atmosphere after etching.
3. A method for preparing a diamond field effect transistor is characterized by comprising the following steps:
forming a hydrogen termination on a diamond substrate;
forming an ohmic contact metal layer on the hydrogen terminal diamond, wherein the ohmic contact metal layer comprises two electrodes which are arranged at intervals, and at least part of the hydrogen terminal covered by the ohmic contact metal layer and the hydrogen terminal between the two electrodes are conductive channel regions;
forming a dielectric layer on the ohmic contact metal layer and the hydrogen terminal, and forming an etching groove exposing the hydrogen terminal in a region of the dielectric layer corresponding to the conductive channel region;
forming an h-BN dielectric layer on the dielectric layer and in the etching groove, wherein a gate metal groove is arranged in the region of the h-BN dielectric layer corresponding to the etching groove, and the hydrogen terminal is not exposed by the gate metal groove;
and forming a gate metal layer in the gate metal groove and on the h-BN dielectric layer adjacent to the gate metal groove.
4. The method of manufacturing a diamond field effect transistor according to claim 3, wherein forming a hydrogen termination on a diamond substrate comprises:
and preparing a sacrificial layer on the upper surface of the hydrogen terminal diamond in a metal evaporation mode, wherein the metal of the sacrificial layer is Au.
5. A method of fabricating a diamond field effect transistor according to claim 3, wherein forming an ohmic contact metal layer on the hydrogen-terminated diamond comprises:
depositing ohmic contact metal on the upper surface of the hydrogen terminal diamond in a deposition mode to form an ohmic contact metal layer;
and removing the sacrificial layer on the hydrogen terminal diamond by a wet etching mode or a dry etching mode.
6. The method of claim 3, wherein forming a dielectric layer on the ohmic-contact metal layer and the hydrogen terminal, and forming an etched trench in the dielectric layer in a region corresponding to the conductive channel region to expose the hydrogen terminal comprises:
coating photoresist on the dielectric layer, etching the dielectric layer in an etching mode to form the etching groove, and annealing under the condition of hydrogen after etching;
the dielectric layer is a single-layer dielectric or a multi-layer dielectric, and the thickness of the dielectric layer is 1-500 nm;
the method for etching the dielectric layer by the etching method is dry etching or wet etching or combined etching of the dry etching and the wet etching.
7. The method of claim 3, wherein forming an h-BN dielectric layer on the dielectric layer and within the etch trench, and forming a gate metal layer in the gate metal trench and on the h-BN dielectric layer adjacent to the gate metal trench, comprises:
transferring an h-BN dielectric layer on the dielectric layer and in the etching groove in a dry transfer or wet transfer mode, wherein the h-BN dielectric layer is a layer of dielectric or a plurality of layers of dielectric;
and depositing gate metal in a deposition mode to form the gate metal layer, and stripping to form a gate.
8. The method of claim 5, wherein the metal of the ohmic contact metal layer is at least one metal or a plurality of metals that can be formed by an alloying process.
9. A method of manufacturing a diamond field effect transistor according to claim 3, wherein the diamond substrate is single crystal diamond or polycrystalline diamond, and the hydrogen termination is obtained by hydrogen plasma treatment and annealing treatment under hydrogen gas conditions or epitaxial growth under hydrogen gas conditions.
10. The method for preparing a diamond field effect transistor according to claim 7, wherein the shape of the gate metal layer is one or more of a straight gate, a T-shaped gate, a TT-shaped gate, a TTT-shaped gate, a U-shaped gate and a Y-shaped gate.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102403209A (en) * | 2011-11-10 | 2012-04-04 | 上海大学 | Preparation method for ohmic contact electrode based on diamond film field effect transistor |
| JP2019125771A (en) * | 2018-01-11 | 2019-07-25 | 国立研究開発法人物質・材料研究機構 | Mis-type semiconductor device and method of manufacturing the same |
| JP2020035917A (en) * | 2018-08-30 | 2020-03-05 | 学校法人早稲田大学 | Diamond field effect transistor and method of manufacturing the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102403209A (en) * | 2011-11-10 | 2012-04-04 | 上海大学 | Preparation method for ohmic contact electrode based on diamond film field effect transistor |
| JP2019125771A (en) * | 2018-01-11 | 2019-07-25 | 国立研究開発法人物質・材料研究機構 | Mis-type semiconductor device and method of manufacturing the same |
| JP2020035917A (en) * | 2018-08-30 | 2020-03-05 | 学校法人早稲田大学 | Diamond field effect transistor and method of manufacturing the same |
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