WO2019127849A1 - Transition metal nitride material having adjustable high work function, preparation method therefor, and application thereof - Google Patents

Transition metal nitride material having adjustable high work function, preparation method therefor, and application thereof Download PDF

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WO2019127849A1
WO2019127849A1 PCT/CN2018/075415 CN2018075415W WO2019127849A1 WO 2019127849 A1 WO2019127849 A1 WO 2019127849A1 CN 2018075415 W CN2018075415 W CN 2018075415W WO 2019127849 A1 WO2019127849 A1 WO 2019127849A1
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transition metal
metal nitride
work function
substrate
graphite
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Chinese (zh)
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蒋春萍
李玉雄
谷承艳
隋展鹏
刘峰峰
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中国科学院苏州纳米技术与纳米仿生研究所
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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
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/60—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes
    • C23C8/62—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes only one element being applied
    • C23C8/64—Carburising
    • 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
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/60—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes
    • C23C8/62—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes only one element being applied
    • C23C8/68—Boronising
    • 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
    • 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
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02538—Group 13/15 materials
    • H01L21/0254—Nitrides
    • 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
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/0257—Doping during depositing
    • 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
    • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
    • 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
    • H01L29/40—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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
    • H01L33/40—Materials therefor

Definitions

  • the invention relates to a transition metal nitride material, in particular to a transition metal nitride material with high work function and adjustable work function, and the preparation method and application thereof belong to the field of material science.
  • low ohmic contact resistance is the basis for implementing high performance devices.
  • the required metal work function should be less than the work function of the semiconductor. There are many metals in the periodic table that can do this.
  • achieving ohmic contact of a P-type wide bandgap semiconductor is much more difficult because of the need for a metal with a large work function.
  • the largest work function of the existing metal is Pt, but its work function is only 5.65eV, which is much smaller than the work function of the wide bandgap p-type nitride semiconductor material (work function is greater than 6.5eV), so to achieve true "ohm "Contact is very difficult.
  • Transition metal nitride is a kind of ceramic material with high temperature resistance, and its composition changes with the growth process parameters, so its electrical and optical properties will also change with the growth process parameters, and Metallic transition metal nitrides have good electrical conductivity.
  • transition metal nitride films which are often used as barrier layers in metal contact mechanisms in electrical applications, or directly as ohmic contact layers to improve the stability and reliability of ohmic contacts.
  • TiN, ZrN can be obtained as an ohmic contact layer of an n-GaN material or a barrier layer in a metal contact layer, and a contact resistivity of 10 ⁇ (-5)-10 ⁇ (-6) ⁇ cm ⁇ 2 can be obtained.
  • the ohmic contact thus achieved can withstand temperatures above 750 ° C (BP Luther, SEMohney, et al., Semicond. Sci. Technol., 1998, 13: 1322 - 1327; SEMohney, BP Lutheretal., International High Temperature Electronics Conference, 1998, 134-137; LFVoss, L. Staffordetal., ECS Transactions, 2007, 6(2): 191-199).
  • transition metal nitrides in P-type semiconductor contacts has also been reported.
  • LFVoss et al. use TiN, ZrN, and TaN as diffusion barrier layers for P-GaN ohmic contacts, that is, insert TiN, ZrN, and TaN between Ni/Au/Ti/Au to become Ni/Au/(TiN or ZrN or TaN).
  • /Ti/Au contact the study shows that after inserting the barrier layer, annealing at 700 ° C for 1 minute under N 2 atmosphere, the contact resistivity of 2 ⁇ 10 ⁇ (-4) ⁇ ⁇ cm ⁇ 2 is obtained until annealing When the temperature reached 1000 ° C, the contact performance remained stable (LF Voss, L.
  • the main object of the present invention is to provide a class of transition metal nitride materials with adjustable high work function, preparation methods and applications thereof,
  • the technical solution adopted by the present invention includes:
  • Embodiments of the present invention provide a high work function adjustable transition metal nitride material including a transition metal nitride substrate and a doping element doped in the substrate, the doping element including B or C.
  • the doping concentration of the B or C element in the transition metal nitride material is ⁇ 50%.
  • the transition metal nitride material has a work function greater than 5 eV, preferably greater than 6.5 eV.
  • transition metal therein is selected from the group consisting of Ti, Zr, Ta, Cr or Hf.
  • the embodiment of the invention further provides a method for preparing a transition metal nitride material with adjustable high work function, which comprises:
  • annealing temperature is 600-700 ° C
  • annealing time is greater than 0 and ⁇ 1 h, so that boron element in boron nitride or C element of graphite
  • the heat is diffused into the transition metal nitride to obtain a transition metal nitride material having a high work function adjustable.
  • the p-type semiconductor is a group III nitride direct wide bandgap semiconductor material.
  • transition metal nitride includes TiN, ZrN, TaN, CrN or HfN.
  • the method of preparation includes: by adjusting a growth process parameter of the transition metal nitride,
  • the preparation method further comprises: performing a cleaning treatment on the surface of the substrate, followed by growth of the transition metal nitride.
  • the preparation method further comprises: after heat treating the substrate, performing growth of the transition metal nitride.
  • the method of preparation further comprises: after removing the oxide layer on the surface of the substrate, performing the growth of the transition metal nitride.
  • the embodiment of the invention further provides a method for preparing a transition metal nitride material with adjustable high work function, which specifically comprises the steps of:
  • the surface-cleaned substrate is placed in an epitaxial chamber of the pulsed laser deposition apparatus, and the epitaxial chamber is evacuated to obtain a high background vacuum (vacuum degree of 10 -6 Pa);
  • the preparation method further comprises: after heat treating the substrate, performing growth of the transition metal nitride.
  • the preparation method further comprises: after removing the oxide layer on the surface of the substrate, performing growth of the transition metal nitride.
  • the p-type semiconductor is a group III nitride direct wide bandgap semiconductor material.
  • Embodiments of the present invention also provide a high work function adjustable transition metal nitride material prepared by any of the foregoing, having a work function greater than 5 eV, preferably greater than 6.5 eV.
  • Embodiments of the present invention also provide applications of the high work function adjustable transition metal nitride material in the fabrication of semiconductor devices, electronic devices, optoelectronic devices, and the like.
  • the present invention realizes boron or carbon to transition metal nitride by thermal diffusion by growing a composite material of transition metal nitride and boron nitride or graphite and using high temperature in situ annealing. Doping, thereby significantly improving the work function of the transition metal nitride material, and the work function is adjustable with the change of the process parameters, and the work function of the transition metal nitride and the P-type wide band gap semiconductor material can be maximized.
  • the matching is simple, the process is simple, and the process is simple and easy to implement on a large scale.
  • 1 is a UPS work function test result of a transition metal nitride film grown by a method according to an embodiment of the present invention
  • FIG. 2 is an I-V curve of a transition metal nitride film grown by a method according to an embodiment of the present invention in contact with P-GaN.
  • transition metal nitride material In view of the low work function of the existing transition metal nitrides, it is difficult to form ohmic contact with the P-type semiconductor material of the wide band gap, and the inventors have long been studied and practiced to propose a class of high work function adjustable of the present invention. Transition metal nitride material, its preparation process and application.
  • the transition metal nitride material of the present invention having a high work function and adjustable work function can provide a reliable compound conductive material, such as an electrode material, for the realization of a low resistance heat stable P-type wide band gap semiconductor ohmic contact.
  • a high work function adjustable transition metal nitride material provided by an embodiment of the invention includes a transition metal nitride substrate and a doping element doped in the substrate, the doping element comprising B or C.
  • the transition metal nitride material has a work function greater than 5 eV, preferably greater than 6.5 eV.
  • transition metal therein is selected from the group consisting of Ti, Zr, Ta, Cr or Hf.
  • the doping concentration of the B or C element is ⁇ 50% (atomic percent concentration).
  • annealing temperature is 600-700 ° C
  • annealing time is greater than 0 and ⁇ 1 h, so that boron element in boron nitride or C element of graphite
  • the heat is diffused into the transition metal nitride to obtain a transition metal nitride material having a high work function adjustable.
  • the p-type semiconductor is a group III nitride direct wide band gap semiconductor material, preferably such as P-GaN or the like, but is not limited thereto.
  • transition metal nitride includes TiN, ZrN, TaN, CrN or HfN, etc., but is not limited thereto.
  • the method of preparation includes growing the transition metal nitride and the boron nitride or graphite using a pulsed laser deposition process.
  • the preparation method includes at least one of adjusting a growth process parameter of the transition metal nitride, a growth process parameter of the boron nitride or graphite, and a process parameter of the high temperature annealing. Thereby adjusting the work function of the transition metal nitride material.
  • the method of preparation specifically includes the steps of:
  • a transition metal nitride, boron nitride or graphite is sequentially grown on the surface of the substrate.
  • the preparation method specifically comprises: heating the substrate to a temperature of 5-10 ° C / min to 600-650 ° C and holding, holding time is greater than 0 and ⁇ 1 h, complete the substrate The heat treatment further removes organic contaminants on the surface of the substrate and repairs the surface of the substrate.
  • the method of preparation includes pretreating a surface of a substrate with an Ar plasma to remove the oxide layer.
  • the surface-cleaned substrate is placed in an epitaxial chamber of the pulsed laser deposition apparatus, and the epitaxial chamber is evacuated to obtain a high background vacuum (vacuum degree of 10 -6 Pa);
  • the preparation method specifically comprises: heating the substrate to a temperature of 5-10 ° C / min to 600-650 ° C and holding, holding time is greater than 0 and ⁇ 1 h, complete the substrate The heat treatment is followed by adjusting the substrate temperature to the temperature required to grow the transition metal nitride film.
  • the preparation method further includes: after adjusting a substrate temperature to a temperature required for growing the transition metal nitride film, and also generating an Ar plasma by using a discharge device provided by the pulse laser deposition device, and The surface of the substrate is pretreated with the Ar plasma to remove the oxide layer on the surface, and then the discharge device and the Ar gas are turned off.
  • the method of preparation further includes pre-sputtering the transition metal nitride target prior to growing the transition metal nitride film on the substrate.
  • transition metal nitride includes TiN, ZrN, TaN, CrN or HfN, etc., but is not limited thereto.
  • the transition metal nitride film has a thickness of 100 nm or less.
  • the transition metal nitride film has a growth temperature of 600 to 650 °C.
  • the transition metal nitride film has a N 2 gas pressure of 10 Pa or less when grown.
  • the boron nitride film or graphite has a thickness of 20 nm or less.
  • the boron nitride film or graphite has a growth temperature of 600 to 650 °C.
  • the Ar gas pressure at the time of growth of the boron nitride film or graphite is 30 Pa or less.
  • the p-type semiconductor is a group III nitride direct wide band gap semiconductor material, preferably such as P-GaN or the like.
  • a method for growing a high work function adjustable transition metal nitride film includes the following steps:
  • Step 1 Select a P-type semiconductor material (Group III nitride direct wide bandgap semiconductor, preferably P-GaN) as a substrate, and ultrasonically clean the P-type semiconductor material substrate with acetone, ethanol, deionized water, etc., respectively. (Alternatively, other cleaning methods known in the art can be substituted), and then the substrate is blown dry with N 2 ;
  • a P-type semiconductor material Group III nitride direct wide bandgap semiconductor, preferably P-GaN
  • Step 2 placing the substrate into an epitaxial chamber of a pulsed laser deposition apparatus, and vacuuming the epitaxial chamber to obtain a high background vacuum;
  • Step 3 The substrate is heated at a temperature increase rate of 5-10 ° C / min, the substrate is heat treated at 600-650 ° C, and then heated or cooled to reach a desired substrate growth temperature;
  • Step 4 Before the growth, an Ar plasma is generated by using a discharge device provided by the pulse laser deposition device, and the surface of the substrate is pretreated to remove the oxide layer on the surface;
  • Step: 5 Turn off the discharge device, turn off Ar, and pass N 2 gas into the epitaxial chamber to reach the required reaction chamber pressure
  • Step 6 lowering the baffle in front of the substrate, and turning on the laser to pre-sputter the transition metal nitride target;
  • Step 7 removing the baffle and performing growth of a transition metal nitride film of a certain thickness on the substrate;
  • Step 8 turning off the N 2 gas, introducing Ar into the same reaction chamber to reach a desired pressure, and then performing growth of a boron nitride film of a certain thickness;
  • Step 9 performing high temperature in situ annealing on the grown sample
  • Step 10 Cool down, wait for the temperature to drop to room temperature, and take out the sample.
  • the pulsed laser deposition apparatus described in the foregoing step 2 or step 4 has a laser of a KrF excimer laser having a wavelength of 248 nm, a laser pulse width of about 25 ns, and a maximum pulse repetition frequency of about 10 Hz.
  • the transition metal nitride film described in the above step 7 is preferably TiN or ZrN, exhibiting metallic properties, a film thickness of 100 nm or less, a growth temperature of 600 to 650 ° C, and a N 2 gas pressure of 10 Pa or less.
  • the boron nitride film has a thickness of 20 nm or less, a growth temperature of 600 to 650 ° C, and an Ar gas pressure of 30 Pa or less.
  • the work function of the transition metal nitride film can be adjusted by changing the growth gas pressure of the boron nitride film in the step 8.
  • the work function of the transition metal nitride material is also adjustable with process parameters such as pressure, temperature, laser energy, and frequency, thereby maximizing the realization of the P-type wide band gap. Matching of the work function of the semiconductor material.
  • the high-temperature in-situ annealing is performed on the grown transition metal nitride film/boron nitride film double-layer film, and the boron element-to-transition metal nitride film is realized by high-temperature annealing using thermal diffusion.
  • the doping thereby significantly improving the work function of the transition metal nitride film, the process is simple and controllable, the cost is low, and it is advantageous for large-scale implementation, and can effectively guarantee the quality and performance of the product.
  • the boron nitride film may be replaced by graphite or the like, and a transition metal nitride material having a high work function adjustable may also be obtained.
  • the work function of the high work function adjustable transition metal nitride material prepared by any of the foregoing methods provided by the embodiments of the present invention is greater than 5 eV, preferably greater than 6.5 eV.
  • Embodiments of the present invention also provide applications of the high work function adjustable transition metal nitride material in the fabrication of semiconductor devices, electronic devices, optoelectronic devices, and the like.
  • embodiments of the present invention provide an apparatus comprising a semiconductor material and the high work function adjustable transition metal nitride material, the transition metal nitride material forming an ohmic contact with the semiconductor material.
  • the semiconductor material comprises a P-type wide band gap semiconductor material, preferably a Group III nitride direct wide band gap semiconductor material, particularly preferably P-GaN or the like.
  • the device comprises an electronic device or an optoelectronic device.
  • the high work function adjustable transition metal nitride material can be applied to the fabrication of electrodes and the like.
  • Embodiment 1 A method for growing a high work function adjustable transition metal nitride film according to the embodiment includes the following specific steps:
  • Step 1 using P-GaN material, the hole concentration is about 6 ⁇ 10 16 cm -3 , and ultrasonically cleaning the P-GaN material with acetone, ethanol and deionized water, respectively, and then drying it with N 2 ;
  • Step 2 placing the substrate into an epitaxial chamber of a pulsed laser deposition apparatus, and vacuuming the epitaxial chamber to obtain a high background vacuum of about 10 -6 Pa;
  • Step 3 The substrate is heated at a temperature increase rate of about 10 ° C / min, the substrate is heat treated at about 600 ° C, heat treatment time is about 1 h, and then heated to about 650 ° C;
  • Step 4 Before the growth, the Ar plasma (power is about 0.2-0.4 W) is generated by the discharge device provided by the pulse laser deposition device, and the surface of the substrate is sputtered to remove the oxide layer on the surface;
  • the Ar plasma power is about 0.2-0.4 W
  • Step: 5 Turn off the discharge device, turn off Ar, pass N 2 into the epitaxial chamber, the flow rate is about 20sccm, and the pressure of the reaction chamber is about 3Pa;
  • Step 6 Lower the baffle in front of the substrate, turn on the laser, the laser energy is 250-500 mJ, the laser pulse frequency is 1-2HZ, pre-sputter the titanium nitride target, and the sputtering time is about 5-10 min. Remove oxides and other contaminants from the surface;
  • Step 7 removing the baffle to perform growth of a titanium nitride (TiN) film, the growth time is about 20 min, and the thickness is about 20 nm;
  • Step 8 The N 2 gas is turned off, Ar is introduced into the same reaction chamber, the gas pressure is about 7 Pa, and the deposition temperature is still about 650 ° C.
  • the boron nitride film is grown by sputtering a boron nitride target, and the growth time is 20 min. ;
  • Step 9 performing high temperature in situ annealing on the grown sample at a temperature of about 650 ° C, an Ar gas pressure of about 16 Pa, and an annealing time of about 1 h;
  • Step 10 Cool down, wait for the temperature to drop to room temperature, take out the sample and mark it as sample 1.
  • the Ar gas pressure in step 9 was changed to 7 Pa, and the growth of the sample 2 was performed.
  • Embodiment 2 A method for growing a high work function adjustable transition metal nitride film according to the embodiment includes the following specific steps:
  • Step 2 same as the embodiment
  • Step 3 The substrate is heated at a temperature increase rate of about 5 ° C / min, the substrate is heat treated at about 650 ° C, heat treatment time is about 1 h, and then cooled to about 600 ° C;
  • Step 4 same as the embodiment
  • Step: 5 same as the embodiment
  • Step 6 Lower the baffle in front of the substrate, turn on the laser, the laser energy is 250-500 mJ, the laser pulse frequency is 1-2HZ, pre-sputter the chromium nitride target, and the sputtering time is about 5-10 min. Remove oxides and other contaminants from the surface;
  • Step 7 remove the baffle to grow the chromium nitride film, and the growth time is about 20 min;
  • Step 8 The N 2 gas is turned off, Ar is introduced into the same reaction chamber, the gas pressure is about 7 Pa, and the deposition temperature is still about 600 ° C.
  • the boron nitride film is grown by sputtering a boron nitride target, and the growth time is 20 min. ;
  • Step 9 performing high temperature in situ annealing on the grown sample at a temperature of about 700 ° C, an Ar gas pressure of about 20 Pa, and an annealing time of about 0.5 h;
  • Step 10 Cool down, wait for the temperature to drop to room temperature, and take out the sample, which is a CrN film, which exhibits metallicity and a work function of about 7 eV.
  • Embodiment 3 A method for growing a high work function adjustable transition metal nitride film according to the embodiment includes the following specific steps:
  • Step 2 same as the embodiment
  • Step 3 The substrate is heated at a temperature increase rate of about 8 ° C / min, the substrate is heat treated at about 630 ° C, the heat treatment time is about 1 h, and then the temperature is maintained;
  • Step 4 same as the embodiment
  • Step: 5 same as the embodiment
  • Step 6 Lower the baffle in front of the substrate, turn on the laser, the laser energy is 250-500 mJ, the laser pulse frequency is 1-2HZ, pre-sputter the ZrN target, and the sputtering time is about 5-10 min to remove the surface. Oxide and other contaminants;
  • Step 7 remove the baffle to grow the ZrN film, and the growth time is about 20 min;
  • Step 8 shut off the N 2 gas, and carry out the growth of graphite in the same reaction chamber, the thickness of the grown graphite is about 10 nm;
  • Step 9 performing high temperature in situ annealing on the grown sample at a temperature of about 600 ° C, an Ar gas pressure of about 10 Pa, and an annealing time of about 1 h;
  • Step 10 Cool down, wait for the temperature to drop to room temperature, and take out the sample, which is a ZrN film, which exhibits metallicity and a work function of 6.5 eV or more.
  • Embodiment 4 A method for growing a high work function adjustable transition metal nitride film according to this embodiment is basically the same as Embodiments 1 and 2 except that an HfN target is used.
  • the work function of the finally obtained HfN film sample was also above 6.5 eV.
  • Embodiment 5 A method for growing a high work function adjustable transition metal nitride film according to this embodiment is basically the same as Embodiments 1 and 2 except that a TaN target is used. The work function of the final TaN film sample was also above 6.5 eV.
  • the high work function adjustable transition metal nitride material obtained in the foregoing embodiment can be used for preparing a semiconductor device, an electronic device, an optoelectronic device, or the like, wherein the transition metal nitride material can form a good ohm with a semiconductor material such as P-GaN. contact.

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Abstract

A transition metal nitride material having an adjustable high work function, a preparation method therefor, and an application thereof. The preparation method comprises: sequentially growing a transition metal nitride, boron nitride, or graphite on a p-type semiconductor material as a substrate; and performing high-temperature annealing on the obtained boron nitride or graphite/transition metal nitride composite structural material, such that elemental boron in the boron nitride or elemental carbon in the graphite is thermally diffused into the transition metal nitride, to obtain a transition metal nitride material having an adjustable high work function. The obtained transition metal nitride material is doped with elemental B or C, and has a work function greater than 5 ev. The preparation process is simple, efficient, easy to control, and easy to implement on a large scale. The work function is conveniently controlled, and maximizes matching between the work functions of transition metal nitrides and P-type wide band gap semiconductor materials.

Description

高功函数可调的过渡金属氮化物材料、其制备方法及应用Transition metal nitride material with adjustable high work function, preparation method and application thereof 技术领域Technical field
本发明涉及一种过渡金属氮化物材料，特别是一种具有高功函数且功函数可调的过渡金属氮化物材料，其制备方法及应用，属于材料科学领域。The invention relates to a transition metal nitride material, in particular to a transition metal nitride material with high work function and adjustable work function, and the preparation method and application thereof belong to the field of material science.
背景技术Background technique
对于半导体器件，特别是半导体光电子器件来说，低欧姆接触电阻是实现高性能器件的基础。对于n型材料来说，所需要的金属功函数应小于半导体的功函数。在元素周期表中，有很多金属可以实现这一点。相比之下，实现P型宽禁带半导体的欧姆接触则要困难得多，因为需要具有较大功函数的金属。现有金属中功函数最大的就是Pt，但其功函数也只有5.65eV，这远小于宽禁带p型氮化物半导体材料的功函数(功函数大于6.5eV)，因此要达到真正的“欧姆”接触是很困难的。因此，靠单一金属或多组分金属进行功函数调节的能力有限。而且随着器件向着高温、大功率的方向发展，在获得低阻欧姆接触的同时提高其热稳定性也至关重要。过渡金属氮化物是一类陶瓷材料，具有耐高温的性质，而且其组分随着生长工艺参数的变化而变化，因此其电学、光学性质也会随着生长工艺参数的变化而变化，并且具有金属性的过渡金属氮化物具有很好的导电性。目前，有关过渡金属氮化物薄膜的报道有很多，在电学应用方面常作为金属接触机制中的垒层，或直接作为欧姆接触层，以提高欧姆接触的稳定性和可靠性。据报道，将TiN、ZrN作为n-GaN材料的欧姆接触层或者金属接触层中的垒层，能获得10^(-5)-10^(-6)Ω·cm^2的接触电阻率，而且由此实现的欧姆接触能承受750℃以上的高温(B.P.Luther,S.E.Mohney,etal.,Semicond.Sci.Technol.,1998,13:1322–1327；S.E.Mohney,B.P.Lutheretal.,InternationalHighTemperatureElectronicsConference,1998,134-137；L.F.Voss,L.Staffordetal.,ECSTransactions,2007,6(2):191-199)。过渡金属氮化物在P型半导体接触中的应用也有相关报道。L.F.Voss等人利用TiN、ZrN、TaN作为P-GaN欧姆接触的扩散垒层，即在Ni/Au/Ti/Au之间***TiN、ZrN、TaN，变成Ni/Au/(TiN或ZrN或TaN)/Ti/Au接触，研究表明***势垒层后，在N 2气氛下，700℃下退火1分钟，获得了2×10^(-4)Ω·cm^2的接触电阻率，直到退火温度达到1000℃，其接触性能仍然保持稳定(L.F.Voss,L.Staffordet al.,Appl.Phys.Lett.,2007,90(21):2107)。然而，过渡金属氮化物的功函数低，文献报道的TiN 的功函数仅为3.74eV,其与P-GaN接触形成的是肖特基接触(C.A.Dimitriadis,Th.Karakostaset al.,Solid-StateElectronics,1999,43:1969-1972)。而其他的过渡金属氮化物如ZrN、HfN、TaN等的功函数也比较低，一般都小于5eV,因此也难与宽禁带的P型半导体材料形成欧姆接触。另外，仅通过工艺参数的变化改变其组分，从而导致其功函数的变化范围也非常有限。 For semiconductor devices, especially semiconductor optoelectronic devices, low ohmic contact resistance is the basis for implementing high performance devices. For n-type materials, the required metal work function should be less than the work function of the semiconductor. There are many metals in the periodic table that can do this. In contrast, achieving ohmic contact of a P-type wide bandgap semiconductor is much more difficult because of the need for a metal with a large work function. The largest work function of the existing metal is Pt, but its work function is only 5.65eV, which is much smaller than the work function of the wide bandgap p-type nitride semiconductor material (work function is greater than 6.5eV), so to achieve true "ohm "Contact is very difficult. Therefore, the ability to perform work function adjustment by a single metal or multi-component metal is limited. Moreover, as the device develops toward high temperature and high power, it is also important to improve the thermal stability while obtaining low resistance ohmic contact. Transition metal nitride is a kind of ceramic material with high temperature resistance, and its composition changes with the growth process parameters, so its electrical and optical properties will also change with the growth process parameters, and Metallic transition metal nitrides have good electrical conductivity. At present, there are many reports on transition metal nitride films, which are often used as barrier layers in metal contact mechanisms in electrical applications, or directly as ohmic contact layers to improve the stability and reliability of ohmic contacts. It has been reported that TiN, ZrN can be obtained as an ohmic contact layer of an n-GaN material or a barrier layer in a metal contact layer, and a contact resistivity of 10^(-5)-10^(-6) Ω·cm^2 can be obtained. Moreover, the ohmic contact thus achieved can withstand temperatures above 750 ° C (BP Luther, SEMohney, et al., Semicond. Sci. Technol., 1998, 13: 1322 - 1327; SEMohney, BP Lutheretal., International High Temperature Electronics Conference, 1998, 134-137; LFVoss, L. Staffordetal., ECS Transactions, 2007, 6(2): 191-199). The use of transition metal nitrides in P-type semiconductor contacts has also been reported. LFVoss et al. use TiN, ZrN, and TaN as diffusion barrier layers for P-GaN ohmic contacts, that is, insert TiN, ZrN, and TaN between Ni/Au/Ti/Au to become Ni/Au/(TiN or ZrN or TaN). /Ti/Au contact, the study shows that after inserting the barrier layer, annealing at 700 ° C for 1 minute under N 2 atmosphere, the contact resistivity of 2 × 10 ^ (-4) Ω · cm ^ 2 is obtained until annealing When the temperature reached 1000 ° C, the contact performance remained stable (LF Voss, L. Stafford et al., Appl. Phys. Lett., 2007, 90 (21): 2107). However, the work function of transition metal nitrides is low, and the work function of TiN reported in the literature is only 3.74 eV, which forms a Schottky contact with P-GaN (CADimitriadis, Th. Karakostaset al., Solid-State Electronics, 1999). , 43: 1969-1972). The work functions of other transition metal nitrides such as ZrN, HfN, TaN, etc. are also relatively low, generally less than 5 eV, and thus it is difficult to form an ohmic contact with a wide band gap P-type semiconductor material. In addition, only the composition of the process changes its composition, resulting in a very limited range of variation of its work function.
发明内容Summary of the invention
本发明的主要目的在于提供一类高功函数可调的过渡金属氮化物材料、其制备方法及应用，The main object of the present invention is to provide a class of transition metal nitride materials with adjustable high work function, preparation methods and applications thereof,
从而克服现有技术中的不足。Thereby overcoming the deficiencies in the prior art.
为实现前述发明目的，本发明采用的技术方案包括：In order to achieve the foregoing object, the technical solution adopted by the present invention includes:
本发明实施例提供了一种高功函数可调的过渡金属氮化物材料，其包括过渡金属氮化物基材以及掺杂于所述基材内的掺杂元素，所述掺杂元素包括B或C。Embodiments of the present invention provide a high work function adjustable transition metal nitride material including a transition metal nitride substrate and a doping element doped in the substrate, the doping element including B or C.
进一步地，所述过渡金属氮化物材料中B或C元素的掺杂浓度≦50％。Further, the doping concentration of the B or C element in the transition metal nitride material is ≦50%.
进一步地，所述过渡金属氮化物材料的功函数大于5eV，优选大于6.5eV。Further, the transition metal nitride material has a work function greater than 5 eV, preferably greater than 6.5 eV.
进一步地，其中的过渡金属选自Ti、Zr、Ta、Cr或Hf。Further, the transition metal therein is selected from the group consisting of Ti, Zr, Ta, Cr or Hf.
本发明实施例还提供了一种高功函数可调的过渡金属氮化物材料的制备方法，其包括：The embodiment of the invention further provides a method for preparing a transition metal nitride material with adjustable high work function, which comprises:
在作为衬底的p型半导体材料上生长过渡金属氮化物，Growing a transition metal nitride on a p-type semiconductor material as a substrate,
在所述过渡金属氮化物上生长氮化硼或石墨，以及Growing boron nitride or graphite on the transition metal nitride, and
对所获的氮化硼或石墨/过渡金属氮化物复合结构材料进行高温退火，退火温度为600-700℃，退火时间大于0而≦1h，使氮化硼中的硼元素或石墨的C元素热扩散至过渡金属氮化物中，从而获得高功函数可调的过渡金属氮化物材料。High temperature annealing of the obtained boron nitride or graphite/transition metal nitride composite structural material, annealing temperature is 600-700 ° C, annealing time is greater than 0 and ≦ 1 h, so that boron element in boron nitride or C element of graphite The heat is diffused into the transition metal nitride to obtain a transition metal nitride material having a high work function adjustable.
进一步地，所述p型半导体为Ⅲ族氮化物直接宽带隙半导体材料。Further, the p-type semiconductor is a group III nitride direct wide bandgap semiconductor material.
进一步地，所述过渡金属氮化物包括TiN、ZrN、TaN、CrN或HfN。Further, the transition metal nitride includes TiN, ZrN, TaN, CrN or HfN.
在一些实施方案中，所述的制备方法包括：通过调整所述过渡金属氮化物的生长工艺参数、In some embodiments, the method of preparation includes: by adjusting a growth process parameter of the transition metal nitride,
所述氮化硼或石墨的生长工艺参数、所述高温退火的工艺参数中的至少一种，从而调整所述过渡金属氮化物材料的功函数。At least one of a growth process parameter of the boron nitride or graphite, and a process parameter of the high temperature annealing, thereby adjusting a work function of the transition metal nitride material.
在一些实施方案中，所述的制备方法还包括：对衬底表面进行清洁处理后，再进行过渡金属氮化物的生长。In some embodiments, the preparation method further comprises: performing a cleaning treatment on the surface of the substrate, followed by growth of the transition metal nitride.
在一些实施方案中，所述的制备方法还包括：对衬底进行热处理后，再进行过渡金属氮化物的生长。In some embodiments, the preparation method further comprises: after heat treating the substrate, performing growth of the transition metal nitride.
在一些实施方案中，所述的制备方法还包括：去除衬底表面的氧化层后，再进行过渡金属氮 化物的生长。In some embodiments, the method of preparation further comprises: after removing the oxide layer on the surface of the substrate, performing the growth of the transition metal nitride.
本发明实施例还提供了一种高功函数可调的过渡金属氮化物材料的制备方法，其具体包括步骤：The embodiment of the invention further provides a method for preparing a transition metal nitride material with adjustable high work function, which specifically comprises the steps of:
提供p型半导体材料作为衬底；Providing a p-type semiconductor material as a substrate;
将表面清洁的衬底置入脉冲激光沉积设备的外延室，并对外延室抽真空，获得高的本底真空(真空度达到10 -6Pa)； The surface-cleaned substrate is placed in an epitaxial chamber of the pulsed laser deposition apparatus, and the epitaxial chamber is evacuated to obtain a high background vacuum (vacuum degree of 10 -6 Pa);
将衬底温度调节至生长过渡金属氮化物薄膜所需的温度；Adjusting the substrate temperature to the temperature required to grow the transition metal nitride film;
向所述外延室内通入N 2气，直至达到所需的气压； Passing N 2 gas into the epitaxial chamber until the desired gas pressure is reached;
在衬底上进行过渡金属氮化物薄膜的生长；Performing growth of a transition metal nitride film on the substrate;
关闭N 2气，向所述外延室内通入惰性气体至达到所需的气压； Turning off the N 2 gas, introducing an inert gas into the epitaxy chamber to reach a desired gas pressure;
在过渡金属氮化物薄膜上生长氮化硼薄膜或石墨；Growing a boron nitride film or graphite on the transition metal nitride film;
对所获的包含氮化硼薄膜和过渡金属氮化物薄膜的复合结构材料进行高温退火，使氮化硼中的硼元素或石墨中的C元素热扩散至过渡金属氮化物中，从而获得高功函数可调的过渡金属氮化物材料。Performing high-temperature annealing of the obtained composite structural material containing a boron nitride film and a transition metal nitride film to thermally diffuse boron element in boron nitride or C element in graphite into transition metal nitride, thereby obtaining high work A function-adjustable transition metal nitride material.
在一些实施方案中，所述的制备方法还包括：对衬底进行热处理后，再进行过渡金属氮化物的生长。In some embodiments, the preparation method further comprises: after heat treating the substrate, performing growth of the transition metal nitride.
在一些实施方案中，所述的制备方法还包括：去除衬底表面的氧化层后，再进行过渡金属氮化物的生长。In some embodiments, the preparation method further comprises: after removing the oxide layer on the surface of the substrate, performing growth of the transition metal nitride.
进一步地，所述p型半导体为Ⅲ族氮化物直接宽带隙半导体材料。Further, the p-type semiconductor is a group III nitride direct wide bandgap semiconductor material.
本发明实施例还提供了由前述任一种制备的高功函数可调的过渡金属氮化物材料，其功函数大于5eV，优选大于6.5eV。Embodiments of the present invention also provide a high work function adjustable transition metal nitride material prepared by any of the foregoing, having a work function greater than 5 eV, preferably greater than 6.5 eV.
本发明实施例还提供了所述高功函数可调的过渡金属氮化物材料于制备半导体装置、电子器件、光电子器件等之中的应用。Embodiments of the present invention also provide applications of the high work function adjustable transition metal nitride material in the fabrication of semiconductor devices, electronic devices, optoelectronic devices, and the like.
与现有技术相比，本发明通过生长过渡金属氮化物与氮化硼或石墨的复合结构材料的方式，并采用高温原位退火，利用热扩散实现硼元素或碳元素对过渡金属氮化物的掺杂，从而显著提高了过渡金属氮化物材料的功函数，而且该功函数随着工艺参数的变化是可调的，能最大限度的实现过渡金属氮化物与P型宽带隙半导体材料的功函数的匹配，同时实现掺杂的方式简单，工艺简洁，易于大规模实施。Compared with the prior art, the present invention realizes boron or carbon to transition metal nitride by thermal diffusion by growing a composite material of transition metal nitride and boron nitride or graphite and using high temperature in situ annealing. Doping, thereby significantly improving the work function of the transition metal nitride material, and the work function is adjustable with the change of the process parameters, and the work function of the transition metal nitride and the P-type wide band gap semiconductor material can be maximized. The matching is simple, the process is simple, and the process is simple and easy to implement on a large scale.
附图说明DRAWINGS
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明中记载的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a few embodiments described in the present invention, and other drawings can be obtained from those skilled in the art without any inventive effort.
图1为利用本发明一实施例的方法所生长的过渡金属氮化物薄膜的UPS功函数测试结果；1 is a UPS work function test result of a transition metal nitride film grown by a method according to an embodiment of the present invention;
图2为利用本发明一实施例的方法所生长的过渡金属氮化物薄膜与P-GaN接触的I-V曲线。2 is an I-V curve of a transition metal nitride film grown by a method according to an embodiment of the present invention in contact with P-GaN.
具体实施方式Detailed ways
下面将对本发明的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。The technical solutions of the present invention will be described clearly and completely hereinafter, and it is obvious that the described embodiments are a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.
鉴于现有过渡金属氮化物存在的功函数低，难以与宽禁带的P型半导体材料形成欧姆接触等缺陷，本发明人经长期研究和实践，得以提出本发明的一类高功函数可调的过渡金属氮化物材料、其制备工艺及应用。本发明的具有高功函数且功函数可调的过渡金属氮化物材料可以为低阻热稳定的P型宽带隙半导体欧姆接触的实现提供一可靠的化合物导电材料，例如电极材料。In view of the low work function of the existing transition metal nitrides, it is difficult to form ohmic contact with the P-type semiconductor material of the wide band gap, and the inventors have long been studied and practiced to propose a class of high work function adjustable of the present invention. Transition metal nitride material, its preparation process and application. The transition metal nitride material of the present invention having a high work function and adjustable work function can provide a reliable compound conductive material, such as an electrode material, for the realization of a low resistance heat stable P-type wide band gap semiconductor ohmic contact.
本发明实施例提供的一种高功函数可调的过渡金属氮化物材料包括过渡金属氮化物基材以及掺杂于所述基材内的掺杂元素，所述掺杂元素包括B或C。A high work function adjustable transition metal nitride material provided by an embodiment of the invention includes a transition metal nitride substrate and a doping element doped in the substrate, the doping element comprising B or C.
进一步地，所述过渡金属氮化物材料的功函数大于5eV，优选大于6.5eV。Further, the transition metal nitride material has a work function greater than 5 eV, preferably greater than 6.5 eV.
进一步地，其中的过渡金属选自Ti、Zr、Ta、Cr或Hf。Further, the transition metal therein is selected from the group consisting of Ti, Zr, Ta, Cr or Hf.
进一步地，其中B或C元素的掺杂浓度≦50％(原子百分比浓度)。Further, the doping concentration of the B or C element is ≦50% (atomic percent concentration).
本发明实施例提供的一种高功函数可调的过渡金属氮化物材料的制备方法包括：A method for preparing a transition metal nitride material with adjustable high work function according to an embodiment of the invention includes:
在作为衬底的p型半导体材料上生长过渡金属氮化物，Growing a transition metal nitride on a p-type semiconductor material as a substrate,
在所述过渡金属氮化物上生长氮化硼或石墨，以及Growing boron nitride or graphite on the transition metal nitride, and
对所获的氮化硼或石墨/过渡金属氮化物复合结构材料进行高温退火，退火温度为600-700℃，退火时间大于0而≦1h，使氮化硼中的硼元素或石墨的C元素热扩散至过渡金属氮化物中，从而获得高功函数可调的过渡金属氮化物材料。High temperature annealing of the obtained boron nitride or graphite/transition metal nitride composite structural material, annealing temperature is 600-700 ° C, annealing time is greater than 0 and ≦ 1 h, so that boron element in boron nitride or C element of graphite The heat is diffused into the transition metal nitride to obtain a transition metal nitride material having a high work function adjustable.
进一步地，所述p型半导体为Ⅲ族氮化物直接宽带隙半导体材料，优选如P-GaN等，但不限于此。Further, the p-type semiconductor is a group III nitride direct wide band gap semiconductor material, preferably such as P-GaN or the like, but is not limited thereto.
进一步地，所述过渡金属氮化物包括TiN、ZrN、TaN、CrN或HfN等，但不限于此。Further, the transition metal nitride includes TiN, ZrN, TaN, CrN or HfN, etc., but is not limited thereto.
在一些实施方案中，所述的制备方法包括：采用脉冲激光沉积工艺生长形成所述过渡金属氮化物和所述氮化硼或石墨。In some embodiments, the method of preparation includes growing the transition metal nitride and the boron nitride or graphite using a pulsed laser deposition process.
在一些实施方案中，所述的制备方法包括：通过调整所述过渡金属氮化物的生长工艺参数、所述氮化硼或石墨的生长工艺参数、所述高温退火的工艺参数中的至少一种，从而调整所述过渡金属氮化物材料的功函数。In some embodiments, the preparation method includes at least one of adjusting a growth process parameter of the transition metal nitride, a growth process parameter of the boron nitride or graphite, and a process parameter of the high temperature annealing. Thereby adjusting the work function of the transition metal nitride material.
在一些实施方案中，所述的制备方法具体包括步骤：In some embodiments, the method of preparation specifically includes the steps of:
对衬底表面进行清洁处理，Cleaning the surface of the substrate,
对衬底进行热处理，Heat treating the substrate,
将衬底温度调节至生长过渡金属氮化物所需温度，Adjusting the substrate temperature to the temperature required to grow the transition metal nitride,
去除衬底表面的氧化层，Removing the oxide layer on the surface of the substrate,
在衬底表面依次生长过渡金属氮化物、氮化硼或石墨。A transition metal nitride, boron nitride or graphite is sequentially grown on the surface of the substrate.
在一些较佳实施方案中，所述的制备方法具体包括：使衬底以5-10℃/min的升温速率升温至600-650℃并保温，保温时间大于0而≦1h，完成对衬底的热处理，进一步除去衬底表面的有机污染物，并对衬底表面进行修复。In some preferred embodiments, the preparation method specifically comprises: heating the substrate to a temperature of 5-10 ° C / min to 600-650 ° C and holding, holding time is greater than 0 and ≦ 1 h, complete the substrate The heat treatment further removes organic contaminants on the surface of the substrate and repairs the surface of the substrate.
在一些实施方案中，所述的制备方法包括：利用Ar等离子体对衬底表面进行预处理以去除所述的氧化层。In some embodiments, the method of preparation includes pretreating a surface of a substrate with an Ar plasma to remove the oxide layer.
本发明实施例提供的一种高功函数可调的过渡金属氮化物材料的制备方法包括步骤：A method for preparing a transition metal nitride material with adjustable high work function according to an embodiment of the invention includes the following steps:
提供p型半导体材料作为衬底；Providing a p-type semiconductor material as a substrate;
将表面清洁的衬底置入脉冲激光沉积设备的外延室，并对外延室抽真空，获得高的本底真空(真空度达到10 -6Pa)； The surface-cleaned substrate is placed in an epitaxial chamber of the pulsed laser deposition apparatus, and the epitaxial chamber is evacuated to obtain a high background vacuum (vacuum degree of 10 -6 Pa);
将衬底温度调节至生长过渡金属氮化物薄膜所需的温度；Adjusting the substrate temperature to the temperature required to grow the transition metal nitride film;
向所述外延室内通入N 2气体，直至达到所需的气压； Passing N 2 gas into the epitaxial chamber until the desired gas pressure is reached;
在衬底上进行过渡金属氮化物薄膜的生长；Performing growth of a transition metal nitride film on the substrate;
关闭N 2气，向所述外延室内通入惰性气体至达到所需的气压； Turning off the N 2 gas, introducing an inert gas into the epitaxy chamber to reach a desired gas pressure;
在过渡金属氮化物薄膜上生长氮化硼薄膜或石墨；Growing a boron nitride film or graphite on the transition metal nitride film;
对所获的包含氮化硼薄膜或石墨和过渡金属氮化物薄膜的复合结构材料进行高温退火，使氮化硼中的硼元素或石墨中的C元素热扩散至过渡金属氮化物中，从而获得高功函数可调的过渡金属氮化物材料。Performing high-temperature annealing on the obtained composite structural material containing a boron nitride film or a graphite and a transition metal nitride film, thereby thermally diffusing boron element in boron nitride or C element in graphite into transition metal nitride, thereby obtaining Transition metal nitride material with adjustable high work function.
在一些较佳实施方案中，所述的制备方法具体包括：使衬底以5-10℃/min的升温速率升温至600-650℃并保温，保温时间大于0而≦1h，完成对衬底的热处理，之后将衬底温度调节至生长过渡金属氮化物薄膜所需的温度。In some preferred embodiments, the preparation method specifically comprises: heating the substrate to a temperature of 5-10 ° C / min to 600-650 ° C and holding, holding time is greater than 0 and ≦ 1 h, complete the substrate The heat treatment is followed by adjusting the substrate temperature to the temperature required to grow the transition metal nitride film.
在一些实施方案中，所述的制备方法还包括：在将衬底温度调节至生长过渡金属氮化物薄膜所需的温度后，还利用脉冲激光沉积设备自带的放电装置产生Ar等离子体，且以所述Ar等离子体对衬底表面进行预处理以去除表面的氧化层，之后关闭所述的放电装置及Ar气。In some embodiments, the preparation method further includes: after adjusting a substrate temperature to a temperature required for growing the transition metal nitride film, and also generating an Ar plasma by using a discharge device provided by the pulse laser deposition device, and The surface of the substrate is pretreated with the Ar plasma to remove the oxide layer on the surface, and then the discharge device and the Ar gas are turned off.
在一些实施方案中，所述的制备方法还包括：在衬底上生长过渡金属氮化物薄膜之前，先对过渡金属氮化物靶材进行预溅射。In some embodiments, the method of preparation further includes pre-sputtering the transition metal nitride target prior to growing the transition metal nitride film on the substrate.
进一步地，所述过渡金属氮化物包括TiN、ZrN、TaN、CrN或HfN等，但不限于此。Further, the transition metal nitride includes TiN, ZrN, TaN, CrN or HfN, etc., but is not limited thereto.
优选地，所述过渡金属氮化物薄膜的厚度在100nm以下。Preferably, the transition metal nitride film has a thickness of 100 nm or less.
优选地，所述过渡金属氮化物薄膜的生长温度600-650℃。Preferably, the transition metal nitride film has a growth temperature of 600 to 650 °C.
优选地，所述过渡金属氮化物薄膜生长时的N 2气压在10Pa以下。 Preferably, the transition metal nitride film has a N 2 gas pressure of 10 Pa or less when grown.
优选地，所述氮化硼薄膜或石墨的厚度在20nm以下。Preferably, the boron nitride film or graphite has a thickness of 20 nm or less.
优选地，所述氮化硼薄膜或石墨的生长温度为600-650℃。Preferably, the boron nitride film or graphite has a growth temperature of 600 to 650 °C.
优选地，所述氮化硼薄膜或石墨生长时的Ar气压在30Pa以下。Preferably, the Ar gas pressure at the time of growth of the boron nitride film or graphite is 30 Pa or less.
进一步地，所述p型半导体为Ⅲ族氮化物直接宽带隙半导体材料，优选如P-GaN等。Further, the p-type semiconductor is a group III nitride direct wide band gap semiconductor material, preferably such as P-GaN or the like.
在本发明的一些较为具体的实施案例中，一种高功函数可调的过渡金属氮化物薄膜的生长方法包括如下步骤：In some specific embodiments of the present invention, a method for growing a high work function adjustable transition metal nitride film includes the following steps:
步骤1：选取一P型半导体材料(Ⅲ族氮化物直接宽带隙半导体，优选为P-GaN)为衬底，分别用丙酮、乙醇、去离子水等对该P型半导体材料衬底进行超声清洗(当然也可以替代为本领域已知的其它清洗方式)，然后用N 2将衬底吹干； Step 1: Select a P-type semiconductor material (Group III nitride direct wide bandgap semiconductor, preferably P-GaN) as a substrate, and ultrasonically clean the P-type semiconductor material substrate with acetone, ethanol, deionized water, etc., respectively. (Alternatively, other cleaning methods known in the art can be substituted), and then the substrate is blown dry with N 2 ;
步骤2：将所述衬底放入脉冲激光沉积设备的外延室中，对外延室抽真空，获得高的本底真空；Step 2: placing the substrate into an epitaxial chamber of a pulsed laser deposition apparatus, and vacuuming the epitaxial chamber to obtain a high background vacuum;
步骤3：以5-10℃/min的升温速度进行衬底升温，在600-650℃对衬底进行热处理，然后或升温或降温达到所需的衬底生长温度；Step 3: The substrate is heated at a temperature increase rate of 5-10 ° C / min, the substrate is heat treated at 600-650 ° C, and then heated or cooled to reach a desired substrate growth temperature;
步骤4：生长前利用脉冲激光沉积设备自带的放电装置产生Ar等离子体，对衬底表面进行预处理以去除表面的氧化层；Step 4: Before the growth, an Ar plasma is generated by using a discharge device provided by the pulse laser deposition device, and the surface of the substrate is pretreated to remove the oxide layer on the surface;
步骤:5：关闭放电装置，关闭Ar，将N 2气体通入外延室，达到所需的反应室压强； Step: 5: Turn off the discharge device, turn off Ar, and pass N 2 gas into the epitaxial chamber to reach the required reaction chamber pressure;
步骤6：放下衬底前的挡板，开启激光器对过渡金属氮化物靶材进行预溅射；Step 6: lowering the baffle in front of the substrate, and turning on the laser to pre-sputter the transition metal nitride target;
步骤7：移开挡板，在衬底上进行一定厚度的过渡金属氮化物薄膜的生长；Step 7: removing the baffle and performing growth of a transition metal nitride film of a certain thickness on the substrate;
步骤8：关闭N 2气体，在同一反应室中通入Ar，达到所需的压强，接着进行一定厚度的氮化硼薄膜的生长； Step 8: turning off the N 2 gas, introducing Ar into the same reaction chamber to reach a desired pressure, and then performing growth of a boron nitride film of a certain thickness;
步骤9：对所生长的样品进行高温原位退火；Step 9: performing high temperature in situ annealing on the grown sample;
步骤10：降温，待温度降到室温，取出样品。Step 10: Cool down, wait for the temperature to drop to room temperature, and take out the sample.
在一些实施案例中，前述步骤2或步骤4中所述的脉冲激光沉积设备，其激光器为波长为248nm的KrF准分子激光器，激光脉冲宽度约为25ns，最大脉冲重复频率约为10HZ。In some embodiments, the pulsed laser deposition apparatus described in the foregoing step 2 or step 4 has a laser of a KrF excimer laser having a wavelength of 248 nm, a laser pulse width of about 25 ns, and a maximum pulse repetition frequency of about 10 Hz.
前述步骤7中所述的过渡金属氮化物薄膜优选地为TiN、ZrN，呈现金属性，其薄膜厚度在100nm以下，生长温度为600-650℃，N 2气压在10Pa以下。 The transition metal nitride film described in the above step 7 is preferably TiN or ZrN, exhibiting metallic properties, a film thickness of 100 nm or less, a growth temperature of 600 to 650 ° C, and a N 2 gas pressure of 10 Pa or less.
前述步骤8中所述氮化硼薄膜的厚度在20nm以下，生长温度为600-650℃，Ar气压在30Pa以下。其中，通过改变步骤8中氮化硼薄膜的生长气压，可以实现过渡金属氮化物薄膜功函数的调节。另外，本发明的前述实施例中，过渡金属氮化物材料的功函数还随着工艺参数例如气压、温度、激光能量、频率的变化是可调的，因而能最大限度的实现与P型宽带隙半导体材料的功函数的匹配。In the above step 8, the boron nitride film has a thickness of 20 nm or less, a growth temperature of 600 to 650 ° C, and an Ar gas pressure of 30 Pa or less. Wherein, the work function of the transition metal nitride film can be adjusted by changing the growth gas pressure of the boron nitride film in the step 8. In addition, in the foregoing embodiments of the present invention, the work function of the transition metal nitride material is also adjustable with process parameters such as pressure, temperature, laser energy, and frequency, thereby maximizing the realization of the P-type wide band gap. Matching of the work function of the semiconductor material.
本发明的前述实施例中，通过对所生长的过渡金属氮化物薄膜/氮化硼薄膜双层膜进行所述的高温原位退火，通过高温退火利用热扩散实现硼元素对过渡金属氮化物薄膜的掺杂，从而显著提高过渡金属氮化物薄膜的功函数，工艺简单可控，成本低，利于大规模实施，且能有效保障产物的品质和性能。In the foregoing embodiment of the present invention, the high-temperature in-situ annealing is performed on the grown transition metal nitride film/boron nitride film double-layer film, and the boron element-to-transition metal nitride film is realized by high-temperature annealing using thermal diffusion. The doping, thereby significantly improving the work function of the transition metal nitride film, the process is simple and controllable, the cost is low, and it is advantageous for large-scale implementation, and can effectively guarantee the quality and performance of the product.
在前述的实施例中，氮化硼薄膜还可被替代为石墨等，并同样可以获得高功函数可调的过渡金属氮化物材料。In the foregoing embodiments, the boron nitride film may be replaced by graphite or the like, and a transition metal nitride material having a high work function adjustable may also be obtained.
本发明实施例提供的由前述任一种方法制备的高功函数可调的过渡金属氮化物材料的功函数大于5eV，优选大于6.5eV。The work function of the high work function adjustable transition metal nitride material prepared by any of the foregoing methods provided by the embodiments of the present invention is greater than 5 eV, preferably greater than 6.5 eV.
本发明实施例还提供了所述高功函数可调的过渡金属氮化物材料于制备半导体装置、电子器件、光电子器件等之中的应用。Embodiments of the present invention also provide applications of the high work function adjustable transition metal nitride material in the fabrication of semiconductor devices, electronic devices, optoelectronic devices, and the like.
例如，本发明实施例提供了一种装置，包含半导体材料以及所述的高功函数可调的过渡金属氮化物材料，所述过渡金属氮化物材料与半导体材料形成欧姆接触。For example, embodiments of the present invention provide an apparatus comprising a semiconductor material and the high work function adjustable transition metal nitride material, the transition metal nitride material forming an ohmic contact with the semiconductor material.
进一步地，所述半导体材料包括P型宽带隙半导体材料，优选为Ⅲ族氮化物直接宽带隙半导体材料，尤其优选为P-GaN等。Further, the semiconductor material comprises a P-type wide band gap semiconductor material, preferably a Group III nitride direct wide band gap semiconductor material, particularly preferably P-GaN or the like.
进一步地，所述的装置包括电子装置或光电子装置。Further, the device comprises an electronic device or an optoelectronic device.
进一步地，在所述的装置中，所述的高功函数可调的过渡金属氮化物材料可以被应用于制作电极等。Further, in the device, the high work function adjustable transition metal nitride material can be applied to the fabrication of electrodes and the like.
下面结合具体实施例对本发明作进一步详细的说明，所述是对本发明的解释而不是限定。The invention is further described in detail below with reference to the specific embodiments, which are illustrative and not restrictive.
实施例1：本实施例涉及的一种高功函数可调的过渡金属氮化物薄膜的生长方法包括如下具体步骤：Embodiment 1: A method for growing a high work function adjustable transition metal nitride film according to the embodiment includes the following specific steps:
步骤1：采用P-GaN材料，空穴浓度约为6×10 16cm -3，分别用丙酮、乙醇、去离子水对该P-GaN材料进行超声清洗，然后用N 2将其吹干； Step 1: using P-GaN material, the hole concentration is about 6×10 16 cm -3 , and ultrasonically cleaning the P-GaN material with acetone, ethanol and deionized water, respectively, and then drying it with N 2 ;
步骤2：将所述衬底放入脉冲激光沉积设备的外延室中，对外延室抽真空，获得约10 -6Pa的高本底真空； Step 2: placing the substrate into an epitaxial chamber of a pulsed laser deposition apparatus, and vacuuming the epitaxial chamber to obtain a high background vacuum of about 10 -6 Pa;
步骤3：以约10℃/min的升温速度进行衬底升温，在约600℃对衬底进行热处理，热处理时间约为1h，然后升温到约650℃；Step 3: The substrate is heated at a temperature increase rate of about 10 ° C / min, the substrate is heat treated at about 600 ° C, heat treatment time is about 1 h, and then heated to about 650 ° C;
步骤4：生长前利用脉冲激光沉积设备自带的放电装置产生Ar等离子体(功率约为0.2～0.4W)，对衬底表面进行溅射以去除表面的氧化层；Step 4: Before the growth, the Ar plasma (power is about 0.2-0.4 W) is generated by the discharge device provided by the pulse laser deposition device, and the surface of the substrate is sputtered to remove the oxide layer on the surface;
步骤:5：关闭放电装置，关闭Ar，将N 2通入外延室，流量约为20sccm，达到的反应室压强约为3Pa； Step: 5: Turn off the discharge device, turn off Ar, pass N 2 into the epitaxial chamber, the flow rate is about 20sccm, and the pressure of the reaction chamber is about 3Pa;
步骤6：放下衬底前的挡板，开启激光器，激光器能量在250-500mJ，激光脉冲频率为1-2HZ，对氮化钛靶材进行预溅射，溅射时间约为5-10min，以去除表面的氧化层及其他污染物；Step 6: Lower the baffle in front of the substrate, turn on the laser, the laser energy is 250-500 mJ, the laser pulse frequency is 1-2HZ, pre-sputter the titanium nitride target, and the sputtering time is about 5-10 min. Remove oxides and other contaminants from the surface;
步骤7：移开挡板，进行氮化钛(TiN)薄膜的生长，生长时间约为20min，厚度约为20nm；Step 7: removing the baffle to perform growth of a titanium nitride (TiN) film, the growth time is about 20 min, and the thickness is about 20 nm;
步骤8：关闭N 2气体，在同一反应室中通入Ar，气压约为7Pa，沉积温度依然约为650℃，通过溅射氮化硼靶材进行氮化硼薄膜的生长，生长时间为20min； Step 8: The N 2 gas is turned off, Ar is introduced into the same reaction chamber, the gas pressure is about 7 Pa, and the deposition temperature is still about 650 ° C. The boron nitride film is grown by sputtering a boron nitride target, and the growth time is 20 min. ;
步骤9：对所生长的样品进行高温原位退火，温度约为650℃，Ar气压约为16Pa，退火时间约为1h；Step 9: performing high temperature in situ annealing on the grown sample at a temperature of about 650 ° C, an Ar gas pressure of about 16 Pa, and an annealing time of about 1 h;
步骤10：降温，待温度降到室温，取出样品，标记为样品1。Step 10: Cool down, wait for the temperature to drop to room temperature, take out the sample and mark it as sample 1.
以及，在保持其它操作及工艺条件均不变的情况下，改变步骤9中的Ar气压为7Pa，进行样品2的生长。And, while maintaining other operations and process conditions, the Ar gas pressure in step 9 was changed to 7 Pa, and the growth of the sample 2 was performed.
样品1、2生长完成后，利用紫外光电子谱(UPS)对其功函数进行测试，测试结果如图1所示，经计算获得样品1、2号的功函数分别为10.1eV，6.9eV。由测试结果可以看出：采用本实施例生长的TiN薄膜具有高的功函数，而且该TiN薄膜的功函数随着氮化硼薄膜生长气压的变化而变化，更重要的是利用该方法生长的TiN薄膜呈现金属性，其在作为电极时可以与P-GaN呈现线性接触，功函数越高，接触的线性越好，如图2所示。说明利用本发明的方法实现了B元素对TiN的掺杂，获得了高功函数的且功函数可调的金属性的TiN薄膜。经过工艺步骤的优化，有望与P型宽带隙半导体材料进行功函数的匹配，获得真正的良好的欧姆接 触，而且掺杂过程简单易操作。After the growth of samples 1 and 2 was completed, the work function was tested by ultraviolet photoelectron spectroscopy (UPS). The test results are shown in Fig. 1. The work functions of samples 1 and 2 were calculated to be 10.1 eV and 6.9 eV, respectively. It can be seen from the test results that the TiN film grown by the present embodiment has a high work function, and the work function of the TiN film changes with the change of the growth pressure of the boron nitride film, and more importantly, the growth method using the method. The TiN film exhibits metallic properties and can exhibit linear contact with P-GaN when used as an electrode. The higher the work function, the better the linearity of the contact, as shown in FIG. It is explained that the doping of TiN by B element is realized by the method of the invention, and a metallic TiN film with high work function and adjustable work function is obtained. Through the optimization of the process steps, it is expected to match the work function with the P-type wide band gap semiconductor material to obtain a truly good ohmic contact, and the doping process is simple and easy to operate.
实施例2：本实施例涉及的一种高功函数可调的过渡金属氮化物薄膜的生长方法包括如下具体步骤：Embodiment 2: A method for growing a high work function adjustable transition metal nitride film according to the embodiment includes the following specific steps:
步骤1：与实施例相同；Step 1: Same as the embodiment;
步骤2：与实施例相同；Step 2: same as the embodiment;
步骤3：以约5℃/min的升温速度进行衬底升温，在约650℃对衬底进行热处理，热处理时间约为1h，然后降温到约600℃；Step 3: The substrate is heated at a temperature increase rate of about 5 ° C / min, the substrate is heat treated at about 650 ° C, heat treatment time is about 1 h, and then cooled to about 600 ° C;
步骤4：与实施例相同；Step 4: same as the embodiment;
步骤:5：与实施例相同；Step: 5: same as the embodiment;
步骤6：放下衬底前的挡板，开启激光器，激光器能量在250-500mJ，激光脉冲频率为1-2HZ，对氮化铬靶材进行预溅射，溅射时间约为5-10min，以去除表面的氧化层及其他污染物；Step 6: Lower the baffle in front of the substrate, turn on the laser, the laser energy is 250-500 mJ, the laser pulse frequency is 1-2HZ, pre-sputter the chromium nitride target, and the sputtering time is about 5-10 min. Remove oxides and other contaminants from the surface;
步骤7：移开挡板，进行氮化铬薄膜的生长，生长时间约为20min；Step 7: remove the baffle to grow the chromium nitride film, and the growth time is about 20 min;
步骤8：关闭N 2气体，在同一反应室中通入Ar，气压约为7Pa，沉积温度依然约为600℃，通过溅射氮化硼靶材进行氮化硼薄膜的生长，生长时间为20min； Step 8: The N 2 gas is turned off, Ar is introduced into the same reaction chamber, the gas pressure is about 7 Pa, and the deposition temperature is still about 600 ° C. The boron nitride film is grown by sputtering a boron nitride target, and the growth time is 20 min. ;
步骤9：对所生长的样品进行高温原位退火，温度约为700℃，Ar气压约为20Pa，退火时间约为0.5h；Step 9: performing high temperature in situ annealing on the grown sample at a temperature of about 700 ° C, an Ar gas pressure of about 20 Pa, and an annealing time of about 0.5 h;
步骤10：降温，待温度降到室温，取出样品，即为CrN薄膜，其呈现金属性，功函数约7eV。Step 10: Cool down, wait for the temperature to drop to room temperature, and take out the sample, which is a CrN film, which exhibits metallicity and a work function of about 7 eV.
实施例3：本实施例涉及的一种高功函数可调的过渡金属氮化物薄膜的生长方法包括如下具体步骤：Embodiment 3: A method for growing a high work function adjustable transition metal nitride film according to the embodiment includes the following specific steps:
步骤1：与实施例相同；Step 1: Same as the embodiment;
步骤2：与实施例相同；Step 2: same as the embodiment;
步骤3：以约8℃/min的升温速度进行衬底升温，在约630℃对衬底进行热处理，热处理时间约为1h，然后维持该温度；Step 3: The substrate is heated at a temperature increase rate of about 8 ° C / min, the substrate is heat treated at about 630 ° C, the heat treatment time is about 1 h, and then the temperature is maintained;
步骤4：与实施例相同；Step 4: same as the embodiment;
步骤:5：与实施例相同；Step: 5: same as the embodiment;
步骤6：放下衬底前的挡板，开启激光器，激光器能量在250-500mJ，激光脉冲频率为1-2HZ，对ZrN靶材进行预溅射，溅射时间约为5-10min，以去除表面的氧化层及其他污染物；Step 6: Lower the baffle in front of the substrate, turn on the laser, the laser energy is 250-500 mJ, the laser pulse frequency is 1-2HZ, pre-sputter the ZrN target, and the sputtering time is about 5-10 min to remove the surface. Oxide and other contaminants;
步骤7：移开挡板，进行ZrN薄膜的生长，生长时间约为20min；Step 7: remove the baffle to grow the ZrN film, and the growth time is about 20 min;
步骤8：关闭N 2气体，在同一反应室进行石墨的生长，生长石墨的厚度约10nm； Step 8: shut off the N 2 gas, and carry out the growth of graphite in the same reaction chamber, the thickness of the grown graphite is about 10 nm;
步骤9：对所生长的样品进行高温原位退火，温度约为600℃，Ar气压约为10Pa，退火时间 约为1h；Step 9: performing high temperature in situ annealing on the grown sample at a temperature of about 600 ° C, an Ar gas pressure of about 10 Pa, and an annealing time of about 1 h;
步骤10：降温，待温度降到室温，取出样品，即为ZrN薄膜，其呈现金属性，功函数也在6.5eV以上。Step 10: Cool down, wait for the temperature to drop to room temperature, and take out the sample, which is a ZrN film, which exhibits metallicity and a work function of 6.5 eV or more.
实施例4：本实施例涉及的一种高功函数可调的过渡金属氮化物薄膜的生长方法与实施例1、2基本相同，但采用的是HfN靶材。最终所得HfN薄膜样品的功函数也在6.5eV以上。Embodiment 4: A method for growing a high work function adjustable transition metal nitride film according to this embodiment is basically the same as Embodiments 1 and 2 except that an HfN target is used. The work function of the finally obtained HfN film sample was also above 6.5 eV.
实施例5：本实施例涉及的一种高功函数可调的过渡金属氮化物薄膜的生长方法与实施例1、2基本相同，但采用的是TaN靶材。最终所得TaN薄膜样品的功函数也在6.5eV以上。Embodiment 5: A method for growing a high work function adjustable transition metal nitride film according to this embodiment is basically the same as Embodiments 1 and 2 except that a TaN target is used. The work function of the final TaN film sample was also above 6.5 eV.
前述实施例获得的高功函数可调的过渡金属氮化物材料可以用于制备半导体装置、电子器件、光电子器件等，其中所述过渡金属氮化物材料可以与P-GaN等半导体材料形成良好的欧姆接触。The high work function adjustable transition metal nitride material obtained in the foregoing embodiment can be used for preparing a semiconductor device, an electronic device, an optoelectronic device, or the like, wherein the transition metal nitride material can form a good ohm with a semiconductor material such as P-GaN. contact.
需要说明的是，以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。It should be noted that the technical features of the foregoing embodiments may be combined in any combination. For the sake of brevity of description, all possible combinations of the technical features in the foregoing embodiments are not described, however, as long as these technical features are There is no contradiction in the combination and should be considered as the scope of this manual.
以上所述实施例仅表达了本发明的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进，这些都属于本发明的保护范围。因此，本发明专利的保护范围应以所附权利要求为准。The above-described embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims (30)

  1. 一种高功函数可调的过渡金属氮化物材料，其特征在于包括过渡金属氮化物基材以及掺杂于所述基材内的掺杂元素，所述掺杂元素包括B或C，并且所述过渡金属氮化物材料的功函数大于5eV。A high work function adjustable transition metal nitride material characterized by comprising a transition metal nitride substrate and a doping element doped in the substrate, the doping element comprising B or C, and The work function of the transition metal nitride material is greater than 5 eV.
  2. 根据权利要求1所述的高功函数可调的过渡金属氮化物材料，其特征在于，其中的过渡金属选自Ti、Zr、Ta、Cr或Hf。The high work function adjustable transition metal nitride material according to claim 1, wherein the transition metal is selected from the group consisting of Ti, Zr, Ta, Cr or Hf.
  3. 根据权利要求1所述的高功函数可调的过渡金属氮化物材料，其特征在于，所述过渡金属氮化物材料中掺杂的B或C元素的原子百分比浓度≦50％。The high work function adjustable transition metal nitride material according to claim 1, wherein the transition metal nitride material has an atomic percentage concentration of B or C element of ≦50%.
  4. 根据权利要求1所述的高功函数可调的过渡金属氮化物材料，其特征在于，所述过渡金属氮化物材料的功函数大于6.5eV。The high work function adjustable transition metal nitride material according to claim 1, wherein the transition metal nitride material has a work function greater than 6.5 eV.
  5. 一种高功函数可调的过渡金属氮化物材料的制备方法，其特征在于包括：A method for preparing a transition metal nitride material with adjustable high work function, characterized in that:
    在作为衬底的p型半导体材料上生长过渡金属氮化物，Growing a transition metal nitride on a p-type semiconductor material as a substrate,
    在所述过渡金属氮化物上生长氮化硼或石墨，以及Growing boron nitride or graphite on the transition metal nitride, and
    对所获的氮化硼或石墨/过渡金属氮化物复合结构材料进行高温退火，退火温度为600-700℃，退火时间大于0而≦1h，使氮化硼中的硼元素或石墨的C元素热扩散至过渡金属氮化物中，从而获得高功函数可调的过渡金属氮化物材料。High temperature annealing of the obtained boron nitride or graphite/transition metal nitride composite structural material, annealing temperature is 600-700 ° C, annealing time is greater than 0 and ≦ 1 h, so that boron element in boron nitride or C element of graphite The heat is diffused into the transition metal nitride to obtain a transition metal nitride material having a high work function adjustable.
  6. 根据权利要求5所述的制备方法，其特征在于：所述p型半导体为Ⅲ族氮化物直接宽带隙半导体材料；和/或，所述过渡金属氮化物包括TiN、ZrN、TaN、CrN或HfN。The method according to claim 5, wherein the p-type semiconductor is a group III nitride direct wide band gap semiconductor material; and/or the transition metal nitride comprises TiN, ZrN, TaN, CrN or HfN .
  7. 根据权利要求6所述的制备方法，其特征在于：所述p型半导体包括P-GaN。The method according to claim 6, wherein the p-type semiconductor comprises P-GaN.
  8. 根据权利要求5-7中任一项所述的制备方法，其特征在于包括：采用脉冲激光沉积工艺生长形成所述过渡金属氮化物和所述氮化硼或石墨。The preparation method according to any one of claims 5 to 7, characterized in that the transition metal nitride and the boron nitride or graphite are grown by a pulse laser deposition process.
  9. 根据权利要求5-7中任一项所述的制备方法，其特征在于包括：通过调整所述过渡金属氮化物的生长工艺参数、所述氮化硼或石墨的生长工艺参数、所述高温退火的工艺参数中的至少一种，从而调整所述过渡金属氮化物材料的功函数。The preparation method according to any one of claims 5 to 7, comprising: adjusting a growth process parameter of the transition metal nitride, a growth process parameter of the boron nitride or graphite, the high temperature annealing At least one of the process parameters to adjust the work function of the transition metal nitride material.
  10. 根据权利要求5-7中任一项所述的制备方法，其特征在于具体包括步骤：The preparation method according to any one of claims 5 to 7, characterized by comprising the steps of:
    对衬底表面进行清洁处理，Cleaning the surface of the substrate,
    对衬底进行热处理，Heat treating the substrate,
    将衬底温度调节至生长过渡金属氮化物所需温度，Adjusting the substrate temperature to the temperature required to grow the transition metal nitride,
    去除衬底表面的氧化层，Removing the oxide layer on the surface of the substrate,
    在衬底表面依次生长过渡金属氮化物、氮化硼或石墨。A transition metal nitride, boron nitride or graphite is sequentially grown on the surface of the substrate.
  11. 根据权利要求10所述的制备方法，其特征在于还包括：使衬底以5-10℃/min的升温速率升温至600-650℃并保温，保温时间大于0而≦1h，完成对衬底的热处理。The preparation method according to claim 10, further comprising: heating the substrate to a temperature of 5-10 ° C / min to 600-650 ° C and maintaining the holding time for more than 0 and ≦ 1 h to complete the substrate. Heat treatment.
  12. 根据权利要求10所述的制备方法，其特征在于包括：利用Ar等离子体对衬底表面进行预处理以去除所述的氧化层。The method according to claim 10, comprising: pretreating the surface of the substrate with an Ar plasma to remove the oxide layer.
  13. 一种高功函数可调的过渡金属氮化物材料的制备方法，其特征在于包括步骤：A method for preparing a transition metal nitride material with adjustable high work function, comprising the steps of:
    提供p型半导体材料作为衬底；Providing a p-type semiconductor material as a substrate;
    将表面清洁的衬底置入脉冲激光沉积设备的外延室，并对外延室抽真空，使其中的本底真空度达到10 -6Pa； Place the surface cleaned substrate into the epitaxial chamber of the pulsed laser deposition apparatus, and evacuate the epitaxial chamber to achieve a background vacuum of 10 -6 Pa;
    将衬底温度调节至生长过渡金属氮化物薄膜所需的温度；Adjusting the substrate temperature to the temperature required to grow the transition metal nitride film;
    向所述外延室内通入N 2气，直至达到所需的气压； Passing N 2 gas into the epitaxial chamber until the desired gas pressure is reached;
    在衬底上进行过渡金属氮化物薄膜的生长；Performing growth of a transition metal nitride film on the substrate;
    关闭N 2气，向所述外延室内通入惰性气体至达到所需的气压； Turning off the N 2 gas, introducing an inert gas into the epitaxy chamber to reach a desired gas pressure;
    在过渡金属氮化物薄膜上生长氮化硼薄膜或石墨；Growing a boron nitride film or graphite on the transition metal nitride film;
    对所获的包含氮化硼薄膜或石墨和过渡金属氮化物薄膜的复合结构材料进行高温退火，使氮化硼中的硼元素或石墨中的C元素热扩散至过渡金属氮化物中，从而获得高功函数可调的过渡金属氮化物材料。Performing high-temperature annealing on the obtained composite structural material containing a boron nitride film or a graphite and a transition metal nitride film, thereby thermally diffusing boron element in boron nitride or C element in graphite into transition metal nitride, thereby obtaining Transition metal nitride material with adjustable high work function.
  14. 根据权利要求13所述的制备方法，其特征在于还包括：使衬底以5-10℃/min的升温速率升温至600-650℃并保温，保温时间大于0而≦1h，完成对衬底的热处理，之后将衬底温度调节至生长过渡金属氮化物薄膜所需的温度。The preparation method according to claim 13, further comprising: heating the substrate to a temperature of 5-10 ° C / min to 600-650 ° C and maintaining the holding time for more than 0 and ≦ 1 h to complete the substrate. The heat treatment is followed by adjusting the substrate temperature to the temperature required to grow the transition metal nitride film.
  15. 根据权利要求13所述的制备方法，其特征在于还包括：在将衬底温度调节至生长过渡金属氮化物薄膜所需的温度后，还利用脉冲激光沉积设备自带的放电装置产生Ar等离子体，且以所述Ar等离子体对衬底表面进行预处理以去除表面的氧化层，之后关闭所述的放电装置及Ar气。The method according to claim 13, further comprising: after adjusting the substrate temperature to a temperature required for growing the transition metal nitride film, and also generating an Ar plasma by using a discharge device provided by the pulse laser deposition device. And pretreating the surface of the substrate with the Ar plasma to remove the oxide layer of the surface, and then turning off the discharge device and the Ar gas.
  16. 根据权利要求13所述的制备方法，其特征在于还包括：在衬底上生长过渡金属氮化物薄膜之前，先对过渡金属氮化物靶材进行预溅射。The method according to claim 13, further comprising: pre-sputtering the transition metal nitride target prior to growing the transition metal nitride film on the substrate.
  17. 根据权利要求13所述的制备方法，其特征在于：所述过渡金属氮化物包括TiN、ZrN、TaN、CrN或HfN。The method according to claim 13, wherein the transition metal nitride comprises TiN, ZrN, TaN, CrN or HfN.
  18. 根据权利要求13-17中任一项所述的制备方法，其特征在于包括：所述过渡金属氮化物薄膜的厚度在100nm以下。The preparation method according to any one of claims 13-17, characterized in that the transition metal nitride film has a thickness of 100 nm or less.
  19. 根据权利要求18所述的制备方法，其特征在于：所述过渡金属氮化物薄膜的生长温度600-650℃；和/或，所述过渡金属氮化物薄膜生长时的N 2气压在10Pa以下。 The method according to claim 18, wherein the transition metal nitride film has a growth temperature of 600 to 650 ° C; and/or the transition metal nitride film has a N 2 gas pressure of 10 Pa or less.
  20. 根据权利要求13所述的制备方法，其特征在于包括：所述氮化硼薄膜或石墨的厚度在20nm以下。The method according to claim 13, comprising the boron nitride film or graphite having a thickness of 20 nm or less.
  21. 根据权利要求20所述的制备方法，其特征在于：所述氮化硼薄膜的生长温度为600-650℃；和/或，所述氮化硼薄膜或石墨生长时的Ar气压在30Pa以下。The method according to claim 20, wherein the boron nitride film has a growth temperature of 600 to 650 ° C; and/or the Ar pressure of the boron nitride film or graphite is 30 Pa or less.
  22. 根据权利要求13-16中任一项所述的制备方法，其特征在于：所述p型半导体为Ⅲ族氮化物直接宽带隙半导体材料。The preparation method according to any one of claims 13 to 16, wherein the p-type semiconductor is a group III nitride direct wide band gap semiconductor material.
  23. 根据权利要求22所述的制备方法，其特征在于：所述p型半导体包括P-GaN。The method according to claim 22, wherein the p-type semiconductor comprises P-GaN.
  24. 由权利要求4-23中任一项所述方法制备的高功函数可调的过渡金属氮化物材料，其功函数大于5eV。A high work function adjustable transition metal nitride material prepared by the method of any of claims 4-23 having a work function greater than 5 eV.
  25. 根据权利要求24所述的高功函数可调的过渡金属氮化物材料，其特征在于：所述过渡金属氮化物材料的功函数大于6.5eV。The high work function adjustable transition metal nitride material according to claim 24, wherein the transition metal nitride material has a work function greater than 6.5 eV.
  26. 一种装置，包含半导体材料，其特征在于还包含权利要求1、2、3、24、25中任一项所述的高功函数可调的过渡金属氮化物材料，所述过渡金属氮化物材料与半导体材料形成欧姆接触。A device comprising a semiconductor material, characterized by further comprising a high work function adjustable transition metal nitride material according to any one of claims 1, 2, 3, 24, 25, said transition metal nitride material Forming an ohmic contact with the semiconductor material.
  27. 根据权利要求26所述的装置，其特征在于：所述半导体材料包括P型宽带隙半导体材料。The device of claim 26 wherein said semiconductor material comprises a P-type wide band gap semiconductor material.
  28. 根据权利要求27所述的装置，其特征在于：所述半导体材料为Ⅲ族氮化物直接宽带隙半导体材料。The device of claim 27 wherein said semiconductor material is a Group III nitride direct wide bandgap semiconductor material.
  29. 根据权利要求28所述的装置，其特征在于：所述半导体材料为P-GaN。The device of claim 28 wherein said semiconductor material is P-GaN.
  30. 根据权利要求26所述的装置，其特征在于：所述的装置包括电子装置或光电子装置。The device of claim 26 wherein said device comprises an electronic device or an optoelectronic device.
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