WO2020010525A1 - p型AlGaN半导体材料生长方法 - Google Patents

p型AlGaN半导体材料生长方法 Download PDF

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WO2020010525A1
WO2020010525A1 PCT/CN2018/095178 CN2018095178W WO2020010525A1 WO 2020010525 A1 WO2020010525 A1 WO 2020010525A1 CN 2018095178 W CN2018095178 W CN 2018095178W WO 2020010525 A1 WO2020010525 A1 WO 2020010525A1
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semiconductor material
nitrogen
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group iii
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江灏
邱新嘉
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中山大学
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    • H—ELECTRICITY
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    • 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
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    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
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    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02436—Intermediate layers between substrates and deposited layers
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    • 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
    • H01L21/02436—Intermediate layers between substrates and deposited layers
    • H01L21/02494—Structure
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    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
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    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
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    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/0257—Doping during depositing
    • H01L21/02573—Conductivity type
    • H01L21/02579—P-type
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    • 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
    • H01L21/02584—Delta-doping
    • H—ELECTRICITY
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    • 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
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/0262—Reduction or decomposition of gaseous compounds, e.g. CVD

Definitions

  • the invention relates to the technical field of epitaxial growth of p-type AlGaN semiconductor materials, and in particular, to a method for preparing p-type AlGaN semiconductor materials by using a surfactant to assist delta doping.
  • the present invention is an improved invention based on the invention patent previously applied for and authorized by the applicant as "a method for preparing p-type GaN and AlGaN semiconductor materials" and patent number 101210396995.9.
  • Group III nitrides also called GaN-based materials
  • the third-generation semiconductor materials have the characteristics of large forbidden band width, direct band gap (high photoelectric conversion efficiency), stable chemical properties, strong thermal conductivity, and high breakdown voltage.
  • optoelectronic devices with high photoelectric conversion efficiency and high response speed such as blue-green light-emitting diodes, semiconductor lasers and ultraviolet photodetectors
  • high temperature, high voltage, and high-power electronic devices such as high electron mobility transistors and high power switching field effect transistors, etc.
  • III-nitride-based light-emitting devices have been commercialized and widely used.
  • III-nitride semiconductors there are still many basic material problems for III-nitride semiconductors, and the conductivity control of p-doped GaN-based materials is one of them.
  • the low doping efficiency of p-type wide band gap GaN and AlGaN semiconductor materials still restricts the development of device applications.
  • Magnesium as the acceptor doping element of GaN-based materials that are currently widely used and have high doping efficiency, has a high ionization energy (about 120 to 180 meV) in the material, so the holes of p-type GaN-based materials The concentration is still at a low level, generally around 5 ⁇ 10 17 cm ⁇ 3 .
  • a higher concentration of magnesium atoms needs to be doped; however, as the amount of magnesium atoms is increased, the crystal quality of the epitaxial layer is greatly reduced, and compensating defects and dislocations are increased. As a result, the self-compensation effect of doping magnesium atoms is enhanced, which prevents the increase of hole concentration.
  • the doped magnesium atoms are limited by the solid solubility.
  • the doping concentration of magnesium reaches 10 19 cm ⁇ 3 , it is usually accompanied by the generation of Mg-N complexes, which limits the substitution of magnesium atoms. Quantity.
  • delta-doped growth method GaN: ⁇ -Mg Grown by MOVPE : Structural properties and their effect on the electronic and optical behavior, Journal of Crystal Growth, 310, 13-21, 2008
  • MOVPE Metal Organic Chemical Vapor Deposition
  • This method of doping in a limited region of the epitaxial layer can increase the doping amount of magnesium atoms, and at the same time, it can also modulate the energy band to a certain extent to reduce the acceptor ionization energy.
  • the method itself does not suppress compensating defects in the epitaxial layer, and the band modulation (reduction of acceptor ionization energy) is also limited; the superlattice-doped growth method (Polarization ⁇ enhanced Mg doping of AlGaN / GaN superlattices, APPLIED PHYSICSLETTERS, VOLUME 75, NUMBER 16, 1999), that is, semiconductor materials with different band gap widths are alternately grown through short periods, and the epitaxial layers of the material with the wider band gap or the epitaxial layers of the two materials are doped.
  • the conduction and valence bands of the two materials will have the same periodic oscillations as the superlattice period.
  • the acceptor ionization energy can be effectively reduced and the hole concentration can be increased.
  • this method can make good use of the two-dimensional hole gas formed by the band bending of the hetero interface to obtain a higher hole concentration, superlattice doping cannot increase the doping concentration of magnesium, nor can it improve the donor. Sexual compensation effect.
  • the superlattice structure is composed of two semiconductor materials with different band gap widths grown alternately, it will have a negative impact on the carrier transport, light emission, or incident absorption in optoelectronic devices; adopting acceptor-donor Co-doped method (High Doped p-Type GaN (Grown, Alternative, Co-Doping Technique, Mat.Res.Soc.Symp.Proc.Vol.719, 2002), although the use of Coulomb interactions between acceptors and donors can effectively reduce the Ionization energy, but the growth window of this method is very narrow, it is difficult to realize, and it is not conducive to large-scale production and commercial application.
  • the improvement of doping efficiency and conductivity of p-type AlGaN / GaN-based materials face problems such as reducing ionization energy, increasing magnesium doping concentration, suppressing compensating defects, and considering the feasibility of epitaxial growth. .
  • the object of the present invention is to provide an improved doping technology based on a surfactant-assisted magnesium delta-doped p-type AlGaN method, that is, by improving the interface of the magnesium delta-doping, a further significant increase in exposure is achieved.
  • the doping concentration of the main magnesium atom in the AlGaN layer before and after the delta doping interface increases the oscillation of the Al composition at the delta doping interface (reducing the ionization energy and increasing the concentration of the two-dimensional hole gas), reducing the concentration in the layer Dislocations, improving the quality of crystallization, thereby increasing the doping efficiency of magnesium, and obtaining a high hole concentration and high conductivity p-type AlGaN semiconductor material growth method.
  • the technical solution provided by the present invention is: a method for growing a p-type AlGaN semiconductor material, the semiconductor material is grown on the base material layer by an epitaxial growth method, and is doped with no less than one identical magnesium delta Periodic structure composition.
  • ammonia gas or dimethylhydrazine nitrogen is used as the group five nitrogen source; trimethylgallium or triethylgallium is used as the group gallium source, and trimethylaluminum or triethylaluminum is used as the source.
  • Group III aluminum source using trimethylindium or triethylindium as the group III indium source, collectively referred to as the group III metal source; trimethylindium or triethylindium is also used as a surfactant, and specifically includes the following steps:
  • (1) Deposition of unintentional doped layer using hydrogen, nitrogen or a mixture of hydrogen and nitrogen as a carrier gas, keeping the Group 5 nitrogen source continuously in, the Group III gallium source, the group III aluminum source, and the surfactant, and depositing Unintentionally doped layer; when depositing this layer, pass trimethylindium or triethylindium surfactant to assist the deposition;
  • Gallium source access Use hydrogen, nitrogen, or a hydrogen-nitrogen mixed gas as the carrier gas to maintain continuous access of the dimagnesium acceptor dopant, maintain the Group 5 nitrogen source, the Group 3 aluminum source, and the surfactant Disconnect and pass in the Group III gallium source, enhance the diffusion of acceptor-doped magnesium atoms in the lattice of the AlGaN semiconductor material, and increase the efficiency of acceptor incorporation; meanwhile, improve the composition change of AlGaN at the interface on both sides of the interface and enhance Band modulation at the interface reduces the activation energy of the acceptor;
  • step (5) The semiconductor material having the required growth thickness in step (5) is thermally annealed in a nitrogen environment to break the Mg-H bond and activate the acceptor to dope magnesium atoms to obtain a p-type AlGaN semiconductor material.
  • the p-type AlGaN semiconductor material growth method of the present invention is not limited to growth on a certain type of base material, and has a wide range of applications.
  • the base material can be a heterogeneous substrate (such as: sapphire, silicon, gallium arsenide, lithium aluminate, gallium Lithium acid, silicon carbide or magnesium oxide, etc.) or homogeneous substrates (Group III nitride, gallium nitride, aluminum nitride, etc.), or directly on AlGaN, n-AlGaN, or other semiconductor material layers can be used Grow.
  • the epitaxial growth method uses a metal organic chemical vapor deposition (MOCVD) method.
  • MOCVD metal organic chemical vapor deposition
  • a P-type AlGaN semiconductor material grown by a surfactant-assisted delta doping method has a thickness between 100 nm and 1000 nm and a growth temperature of 800 ° C to 1280 ° C.
  • the time for disconnecting the Group III gallium source, the Group III aluminum source, and the surfactant in the step (2) is 15s-45s, and the step (3) is passed through the The time is 12s-84s, and the time for accessing the group III gallium source in the step (4) is 3-20s.
  • the above four steps are cycled for 10-100 cycles.
  • the annealing temperature is 500 ° C to 980 ° C, and the annealing time is 30s to 3000s.
  • the method for surfactant-assisted delta doping growth of p-type AlGaN semiconductor materials in the present invention has the following beneficial effects:
  • the indium atoms are more easily desorbed, which can provide more lattice vacancies to the acceptor.
  • the main doped magnesium atoms are filled, thereby increasing the number of acceptor doped magnesium atoms and increasing the efficiency of acceptor doped magnesium atoms.
  • this growth interruption process suppresses the upward climb of the epitaxial layer dislocations, thereby reducing the dislocation density of the epitaxial layer and improving the material's Crystal quality, reducing compensating defects and increasing hole concentration.
  • the step of adding a gallium source to the growth method of the present invention has the following beneficial effects:
  • the step of “gallium source access” is added to supplement the gallium source on the delta doping surface, so that More gallium atoms are incorporated into the previous layer and the next layer of AlGaN, increasing the Ga component in AlGaN on both sides of the doped interface, and reducing the substitution formation energy of magnesium atoms, thereby increasing the acceptor. Incorporation efficiency of magnesium atoms in the upper and lower AlGaN layers; in addition, after the magnesium source is passed in, the gallium source is passed in, which can enhance the retention of magnesium atoms on the surface of the previous layer of AlGaN and increase the probability of its incorporation.
  • the average concentration of the acceptor doped magnesium atoms has increased from 1.1 ⁇ 10 19 cm -3 to 1.6 ⁇ 10 19 cm -3 or more, which is an increase of more than 40%.
  • the triethylindium surfactant assisted the magnesium delta doping of 1.3 ⁇ 10 19 cm -3 to more than 1.6 ⁇ 10 19 cm -3 , with an increase of more than 23%.
  • the step of "gallium source access" is added, and the supplementation of the gallium source enables the Ga atoms to fill due to the purge.
  • the delta group vacancies on the previous layer of AlGaN brought by the delta and delta doping steps reduce defect formation, improve interface roughness, reduce the incorporation of other donor impurities, and also allow more Ga to be incorporated into In the AlGaN layer grown in the latter layer, the Al component in the AlGaN layer before and after the delta doped interface plays an effective modulation role, which increases the oscillation range of the Al component and reduces the thermal activation of the acceptor doped magnesium.
  • the step of "gallium source access" is added, because the surface migration of Ga atoms is better than Al atoms, so that The lateral growth of AlGaN during the deposition process is enhanced, the epitaxial layer is subject to greater compressive stress, and the dislocations of the epitaxial layer extending upward are more likely to be closed, thereby reducing the dislocation density and improving the crystal quality of the material.
  • the epitaxial growth method of the p-type AlGaN semiconductor material on the base material of the present invention is not limited to a certain type of base material, it has a wide range of applications, and the base material may be a heterogeneous substrate (such as: sapphire, silicon, arsenide) Gallium, lithium aluminate, lithium gallate, silicon carbide or magnesium oxide, etc.) or homogeneous substrate (Group III nitride, gallium nitride, aluminum nitride, etc.), or directly on AlGaN, n-AlGaN, or other Can be grown on layers of semiconductor materials.
  • a heterogeneous substrate such as: sapphire, silicon, arsenide
  • Gallium lithium aluminate, lithium gallate, silicon carbide or magnesium oxide, etc.
  • homogeneous substrate Group III nitride, gallium nitride, aluminum nitride, etc.
  • the invention can improve the crystal quality, increase the doping concentration of the acceptor doped magnesium atom, reduce the acceptor ionization energy, and suppress the self-compensation effect, thereby obtaining a p-type AlGaN semiconductor material with good crystal quality and high hole concentration.
  • this epitaxial growth method is not limited to substrates and templates, and has a wide range of applications.
  • the average concentration of the dopant-doped magnesium atoms grown by the epitaxial growth method provided by the present invention is generally from conventionally doped.
  • 1.1 ⁇ 10 19 cm -3 increased to 1.6 ⁇ 10 19 cm -3 or more, with a 40% increase, or 1.3 ⁇ 10 19 cm -3 from trimethylindium or triethylindium surfactant assisted by magnesium delta doping It has been increased to more than 1.6 ⁇ 10 19 cm -3 , which is an increase of more than 23%.
  • the hole concentration has been increased from 1.59 ⁇ 10 18 cm -3 to 8.2 ⁇ 10 18 cm -3, which is more than 4 times.
  • the indium surfactant-assisted magnesium delta-doped 4.75 ⁇ 10 18 cm -3 has been increased to more than 8.2 ⁇ 10 18 cm -3, which is more than 1.7 times.
  • FIG. 1 is a schematic diagram of a growth flow of a p-type AlGaN semiconductor material according to the present invention
  • FIG. 2 is a growth timing diagram of a p-type AlGaN semiconductor material according to the present invention.
  • FIG. 3 is a schematic diagram of an epitaxial growth structure of the p-type AlGaN semiconductor material of Embodiment 1-2.
  • FIG. 1 and FIG. 2 A method for growing a p-type AlGaN semiconductor material disclosed in the present invention is shown in FIG. 1 and FIG. 2.
  • the semiconductor material is grown on the base material layer by an epitaxial growth method, and the periodic structure is doped with no less than one identical magnesium delta.
  • composition during the growth process, using ammonia or dimethyl hydrazine nitrogen as the Group 5 nitrogen source; using trimethylgallium or triethylgallium as the group III gallium source, and using trimethylaluminum or triethylaluminum as the group III
  • An aluminum source, trimethylindium or triethylindium is used as a group III indium source, collectively referred to as a group III metal source; trimethylindium or triethylindium is also used as a surfactant, and specifically includes the following steps:
  • (1) Deposition of unintentional doped layer use hydrogen, nitrogen or hydrogen-nitrogen mixed gas as the carrier gas, keep the Group 5 nitrogen source continuously in, and connect the group III gallium source, group III aluminum source, and surfactant, and grow Unintentionally doped layer; when depositing this layer, pass trimethylindium or triethylindium surfactant to assist the deposition;
  • Gallium source access Use hydrogen, nitrogen, or a hydrogen-nitrogen mixed gas as the carrier gas to maintain continuous access of the dimagnesium acceptor dopant, maintain the Group 5 nitrogen source, the Group 3 aluminum source, and the surfactant Disconnect and pass in the Group III gallium source, enhance the diffusion of acceptor-doped magnesium atoms in the lattice of the AlGaN semiconductor material, and increase the efficiency of acceptor incorporation; meanwhile, improve the composition change of AlGaN at the interface on both sides of the interface and enhance Band modulation at the interface reduces the activation energy of the acceptor;
  • step (5) The semiconductor material having the required growth thickness in step (5) is thermally annealed in a nitrogen environment to break the Mg-H bond and activate the acceptor to dope magnesium atoms to obtain the p-type AlGaN semiconductor material of the present invention.
  • the epitaxial growth structure of the p-type AlGaN semiconductor material of the present invention includes a substrate 101, a buffer layer or a transition layer 102, an unintentionally doped layer 103, and an acceptor doped layer (p-type AlGaN semiconductor material layer). 104.
  • the substrate 101 is a sapphire substrate.
  • a buffer layer 102 is grown on the substrate 101 by a metal organic chemical vapor deposition (MOCVD) epitaxial growth method, and a buffer layer is formed by metal organic chemical vapor deposition (MOCVD) epitaxial growth.
  • MOCVD metal organic chemical vapor deposition
  • An unintentionally doped AlGaN layer 103 is grown, and a p-type AlGaN semiconductor material layer 104 is grown on the unintentionally doped AlGaN layer 103 by using a metal organic chemical vapor deposition (MOCVD) epitaxial growth method.
  • MOCVD metal organic chemical vapor deposition
  • ammonia gas is used as the group five nitrogen source; trimethylgallium is used as the group gallium source, and trimethylaluminum is used as the group three aluminum source; trimethylindium is used as a surfactant.
  • ammonia gas is used as the group five nitrogen source; trimethylgallium is used as the group gallium source, and trimethylaluminum is used as the group three aluminum source; trimethylindium is used as a surfactant.
  • the substrate 101 is placed in a reaction chamber, and an epitaxial structure shown in FIG. 3 is grown on the substrate 101 by a metal organic chemical vapor deposition (MOCVD) epitaxial growth method.
  • MOCVD metal organic chemical vapor deposition
  • the buffer layer 102 is an unintentionally doped AlN material grown at a high temperature and has a thickness of 300 nm. Using hydrogen as a carrier gas, a Group III aluminum source and a Group V nitrogen source growth buffer layer 102 were simultaneously introduced into the reaction chamber, and the growth temperature was 1160 ° C.
  • the unintentionally doped AlGaN layer 103 is an unintentionally doped AlGaN material grown at a high temperature, and its thickness is 500 nm. Hydrogen is used as a carrier gas, and a Group III gallium source, a Group III aluminum source, and a Group III nitrogen source are simultaneously introduced into the reaction chamber to grow an unintentionally doped AlGaN layer 103, and the growth temperature is 1160 ° C.
  • the p-type AlGaN semiconductor material layer 104 is a p-type AlGaN semiconductor material grown using a surfactant-assisted delta doping method, and has a thickness of 500 nm and a growth temperature of 1080 ° C.
  • the p-type AlGaN semiconductor material is composed of no less than one identical magnesium delta-doped periodic structure.
  • the growth method specifically includes the following six steps:
  • Deposition of an unintentionally doped AlGaN layer Use hydrogen as a carrier gas, keep the Group 5 nitrogen source continuously in, and pass in a Group III gallium source, Group III aluminum source, and trimethylindium surfactant to deposit an unintentionally doped AlGaN Floor;
  • Purge Use hydrogen as a carrier gas, keep the Group 5 nitrogen source continuously connected, disconnect the Group III gallium source, the Group III aluminum source, and the surfactant for 30s, and purge the surface of the unintentionally doped AlGaN layer that has grown, so that Al, Ga and In atoms of the Group III metals deposited on the surface are desorbed;
  • Doping Use hydrogen as a carrier gas, keep the Group 5 nitrogen source continuously connected, keep the Group III gallium source, the Group III aluminum source, and the surfactant disconnected, and pass in the magnesium-cene acceptor dopant for 48s, so that The main magnesium atom enters the lattice of AlGaN;
  • Gallium source access Use hydrogen as a carrier gas to maintain continuous access to the dimagnesium acceptor dopant, keep the Group 5 nitrogen source, Group 3 aluminum source, and surfactant disconnected, and access the Group 3 gallium source for 8s , Enhance the diffusion of acceptor-doped magnesium atoms in the lattice of AlGaN semiconductor materials, improve the efficiency of acceptor incorporation; at the same time, improve the composition change of AlGaN at the interface on both sides of the interface, enhance the band modulation at the interface, and reduce the Main activation energy
  • the semiconductor material that reaches the required growth thickness is thermally annealed in a nitrogen environment to break the Mg-H bond and activate the acceptor doped magnesium atoms.
  • the annealing temperature is 650 ° C and the annealing time is 1500s to obtain a p-type AlGaN semiconductor material.
  • the epitaxial growth structure of the p-type AlGaN semiconductor material of the present invention includes a substrate 101, a buffer layer or a transition layer 102, an unintentionally doped layer 103, and an acceptor doped layer (p-type AlGaN semiconductor material layer). 104.
  • the substrate 101 is a silicon carbide substrate, and a buffer layer 102 is sequentially grown on the substrate 101 by a metal organic chemical vapor deposition (MOCVD) epitaxial growth method, and a metal organic chemical vapor deposition (MOCVD) epitaxy is used on the buffer layer.
  • MOCVD metal organic chemical vapor deposition
  • the growth method produces an unintentionally doped AlGaN layer 103 and a p-type AlGaN semiconductor material layer 104 is grown on the unintentionally doped AlGaN layer 103 by using a metal organic chemical vapor deposition (MOCVD) epitaxial growth method.
  • MOCVD metal organic chemical vapor deposition
  • dimethylhydrazine nitrogen is used as a group five nitrogen source; triethylgallium is used as a group gallium source, triethylaluminum is used as a group three aluminum source; and triethylindium is used as a surfactant , Used in p-type AlGaN semiconductor material layer.
  • the substrate 101 is placed in a reaction chamber, and an epitaxial structure shown in FIG. 3 is grown on the substrate 101 by a metal organic chemical vapor deposition (MOCVD) epitaxial growth method.
  • MOCVD metal organic chemical vapor deposition
  • the buffer layer 102 is an unintentionally doped AlN material grown at a high temperature and has a thickness of 500 nm. Using hydrogen as a carrier gas, the Group III aluminum source and the Group five nitrogen source growth buffer layer 102 were simultaneously introduced into the reaction chamber, and the growth temperature was 1180 ° C.
  • the unintentionally doped AlGaN layer 103 is an unintentionally doped AlGaN material grown at a high temperature, and its thickness is 500 nm. Hydrogen is used as a carrier gas, and a Group III gallium source, a Group III aluminum source, and a Group III nitrogen source are simultaneously introduced into the reaction chamber to grow an unintentionally doped AlGaN layer 103, and the growth temperature is 1180 ° C.
  • the p-type AlGaN semiconductor material layer is a p-type AlGaN semiconductor material grown using a surfactant-assisted delta doping method. Its thickness is 800 nm and its growth temperature is 1000 ° C.
  • the growth method includes the following six steps:
  • Deposition of an unintentionally doped AlGaN layer Use nitrogen as a carrier gas, keep the Group 5 nitrogen source continuously in, and pass in a Group 3 gallium source, Group 3 aluminum source, and triethylindium surfactant to deposit an unintentionally doped AlGaN Floor;
  • Purge Use nitrogen as a carrier gas, keep the Group 5 nitrogen source continuously connected, disconnect the Group III gallium source, the Group III aluminum source, and the surfactant for 35s, and purge the surface of the unintentionally doped AlGaN layer that has grown, so that Al, Ga and In atoms of the Group III metals deposited on the surface are desorbed;
  • Doping Use nitrogen as a carrier gas, keep the Group 5 nitrogen source continuously connected, keep the Group III gallium source, the Group III aluminum source, and the surfactant disconnected, and pass in the magnesium-cene acceptor dopant for 48s, so that The main magnesium atom enters the lattice of AlGaN;
  • Gallium source access Use nitrogen as a carrier gas to maintain continuous access to the dimagnesium acceptor dopant, keep the Group 5 nitrogen source, Group 3 aluminum source, and surfactant disconnected, and pass in the Group 3 gallium source for 10s , Enhance the diffusion of acceptor-doped magnesium atoms in the lattice of AlGaN semiconductor materials, improve the efficiency of acceptor incorporation; at the same time, improve the composition change of AlGaN at the interface on both sides of the interface, enhance the band modulation at the interface, and reduce the Main activation energy
  • the semiconductor material that reaches the required thickness is thermally annealed in a nitrogen environment to break the Mg-H bond and activate the acceptor doped magnesium atoms.
  • the annealing temperature is 550 ° C and the annealing time is 1500s to obtain a p-type AlGaN semiconductor material.
  • the p-type AlGaN semiconductor material of this embodiment is grown on an AlN material substrate layer with a thickness of 500 nm and a growth temperature of 900 ° C.
  • ammonia gas is used as the Group 5 nitrogen source
  • Base gallium is used as a group III gallium source
  • trimethylaluminum is used as a group III aluminum source
  • trimethylindium is used as a surfactant
  • Deposition of an unintentionally doped AlGaN layer Use hydrogen as a carrier gas, keep the Group 5 nitrogen source continuously in, and pass in a Group III gallium source, Group III aluminum source, and triethylindium surfactant to deposit an unintentionally doped AlGaN Floor;
  • Purge Use hydrogen as a carrier gas, keep the Group 5 nitrogen source continuously connected, disconnect the Group III gallium source, the Group III aluminum source, and the surfactant for 40s, and purge the surface of the unintentionally doped AlGaN layer that has grown, so that Al, Ga and In atoms of the Group III metals deposited on the surface are desorbed;
  • Doping Use hydrogen as a carrier gas, keep the Group 5 nitrogen source continuously connected, keep the Group 3 gallium source, the group 3 aluminum source, and the surfactant disconnected, and pass in the magnesium-cene acceptor dopant for 60s, so that The main magnesium atom enters the lattice of AlGaN;
  • Gallium source access Use hydrogen as a carrier gas to maintain continuous access to the dimagnesium acceptor dopant, keep the Group 5 nitrogen source, Group 3 aluminum source, and surfactant disconnected, and access the Group 3 gallium source for 8s , Enhance the diffusion of acceptor-doped magnesium atoms in the lattice of AlGaN semiconductor materials, improve the efficiency of acceptor incorporation; at the same time, improve the composition change of AlGaN at the interface on both sides of the interface, enhance the band modulation at the interface, and reduce the Main activation energy
  • the semiconductor material that has reached the required growth thickness is thermally annealed in a nitrogen environment to break the Mg-H bond and activate the acceptor doped magnesium atoms.
  • the annealing temperature is 550 ° C and the annealing time is 1500s.
  • the p-type of this embodiment is obtained. AlGaN semiconductor material.
  • the p-type AlGaN semiconductor material of Example 1-3 was subjected to a test, wherein the p-type AlGaN semiconductor component content of an aluminum material as in Example 1 was 42%, the average concentration of magnesium doped with acceptor atoms is 1.6 ⁇ 10 19 cm - 3 , the hole concentration is 8.2 ⁇ 10 18 cm -3 , the aluminum component content of the p-type AlGaN semiconductor material in Example 2 is 46%, and the average concentration of the acceptor-doped magnesium atom is 1.8 ⁇ 10 19 cm -3 .
  • the hole concentration is 8.6 ⁇ 10 18 cm -3, and the aluminum component content of the p-type AlGaN semiconductor material in Example 3 is 49%.
  • the average concentration of the dopant-doped magnesium atoms is 2.0 ⁇ 10 19 cm -3 , and the hole concentration is 8.9 ⁇ 10 18 cm -3 .
  • the growth method of the present invention can improve the crystalline quality of p-type AlGaN semiconductor materials, increase the doping concentration of acceptor doped magnesium atoms, reduce the acceptor ionization energy, and suppress its self-compensation effect, thereby obtaining good crystal quality.
  • p-type AlGaN semiconductor materials with high hole concentration are examples of this epitaxial growth method.
  • the semiconductor material also has the above technical effects, and a semiconductor material with excellent performance is obtained.

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Abstract

本发明公开了一种p型AlGaN半导体材料的生长方法，所述半导体材料采用在表面活性剂辅助镁delta掺杂中加入"镓源通入"步骤的技术方法进行生长，在p型AlGaN半导体材料生长过程中使用氨气或二甲肼氮作为五族氮源,使用三甲基镓或三乙基镓作为三族镓源，使用三甲基铝或三乙基铝作为三族铝源，三甲基铟或三乙基铟作为三族铟源，统称为三族金属源，三甲基铟或三乙基铟也作为表面活性剂，在受主掺杂层中使用。采用本发明方法可改善结晶质量，提高受主掺杂镁原子的掺杂浓度，通过增强价带调制降低受主离化能，并进一步抑制自补偿效应，从而获得高晶体质量以及高空穴浓度的p型AlGaN半导体材料。

Description

p型AlGaN半导体材料生长方法 技术领域
本发明涉及p型AlGaN半导体材料的外延生长技术领域，尤其涉及一种采用表面活性剂辅助delta掺杂制备p型AlGaN半导体材料的方法。
 背景技术
本发明是申请人在先申请并授权的名称为“一种p型GaN与AlGaN半导体材料的制备方法”、专利号为101210396995.9的发明专利基础上的改进发明。
三族氮化物(也称作GaN基材料)作为第三代半导体材料，具有禁带宽度大、直接带隙(光电转化效率高)、化学性能稳定、热导能力强以及击穿电压高等特点。基于该类半导体材料可以制作出高光电转换效率、高响应速度的光电子器件(如蓝绿光发光二极管、半导体激光器和紫外光电探测器)以及耐高温、耐高压、适用于大功率的电子器件(如高电子迁移率晶体管和大功率开关场效应晶体管等)。
随着最近三十年人们对三族氮化物材料和器件的不断研究，目前基于三族氮化物的发光器件已经实现了商用化并得到了广泛的应用。但是针对三族氮化物半导体仍有许多基础的材料问题没有很好地解决，而p型掺杂GaN基材料的电导控制就是其中之一。目前，p型宽禁带GaN和AlGaN半导体材料的低掺杂效率依然制约着器件应用的发展。镁作为当前普遍使用且掺杂效率较高的GaN基材料的受主掺杂元素，在材料中有较高的离化能(约为120至180 meV)，因此p型GaN基材料的空穴浓度仍处于较低水平，一般在5×10 17cm ‑3左右。若要获得更高的空穴浓度，则需要掺入更高浓度的镁原子；但是，随着镁原子掺入量的增大，外延层晶体质量大幅下降，补偿性缺陷和位错增多，从而导致镁原子掺杂的自补偿效应增强，阻碍空穴浓度的提高。另一方面，掺杂的镁原子受固溶度的限制，当镁的掺杂浓度达到高10 19cm ‑3时，通常伴随着Mg-N络合物的产生，限制了替位镁原子的数量。
为了提高p型GaN和AlGaN的掺杂效率，研究者提出了许多方法，其中主要包括delta掺杂、超晶格结构掺杂以及受主‑施主共掺杂等。所谓delta掺杂的生长方法(GaN:δ‑Mg grown by MOVPE : Structural properties and their effect on the electronic and optical behavior，Journal of Crystal Growth，310，13–21，2008)是在断开三族源(如镓源、铝源)的同时通入受主掺杂镁源，使得受主掺杂镁原子在材料内部呈现类似delta函数的分布。这种通过在外延层限定区域内的掺杂方法可提高镁原子的掺杂量，同时也能对能带进行一定程度的调制，降低受主离化能。但是，该方法本身并没有针对外延层中的补偿性缺陷进行抑制，能带调制（受主离化能降低）效果也有限；超晶格结构掺杂的生长方法(Polarization‑enhanced Mg doping of AlGaN/GaN superlattices，APPLIED  PHYSICS LETTERS，VOLUME 75，NUMBER 16，1999)，也即通过短周期交替生长不同禁带宽度的半导体材料，并对禁带较宽的材料外延层或两种材料的外延层进行掺杂。由于在两种材料的界面处将产生能带的断续，其导带和价带将产生同超晶格周期相同的周期性振荡。通过控制、调节价带界面带阶振荡的周期和振幅，可有效降低受主离化能、提高空穴浓度。该方法虽然可以很好地利用异质界面的能带弯曲形成的二维空穴气来获得更高的空穴浓度，但是超晶格掺杂并不能提高镁的掺杂浓度，也无法改善施主性补偿效应。此外，由于超晶格结构是由两种不同禁带宽度的半导体材料交替堆叠生长构成的，对光电子器件中载流子的输运、光发射或入射吸收都会有负面影响；采用受主‑施主共掺杂的方法(High Doped p‑Type GaN Grown by Alternative Co‑Doping Technique，Mat.Res.Soc.Symp.Proc.Vol.719，2002)，虽然可以通过利用受主‑施主之间的库伦作用来有效地降低受主掺杂镁原子的离化能，但该方法的生长窗口非常窄，实现难度大，也不利于大规模的生产和商业化应用。
综上所述，p型AlGaN /GaN基材料掺杂效率的改善和电导性的提高面临着降低离化能、提高镁掺杂浓度、抑制补偿性缺陷并兼顾外延生长的可行性等方面的问题。
 技术问题
针对现有技术的缺点，本发明目的是提供一种基于表面活性剂辅助镁delta掺杂p型AlGaN方法的改进性掺杂技术，即通过对镁delta掺杂的界面的改善，进一步显著提高受主镁原子在delta掺杂界面前、后AlGaN层中的掺杂浓度，增大delta掺杂界面处的Al组分振荡（降低离化能并提高二维空穴气的浓度），减少层中位错、提高结晶质量，从而提高镁掺杂效率、获得高空穴浓度与高电导性p型AlGaN半导体材料的生长方法。
 技术解决方案
为实现上述发明目的，本发明提供的技术方案为：一种p型AlGaN半导体材料生长方法，所述半导体材料在基体材料层上采用外延生长方法生长，由不少于一个相同的镁delta掺杂周期结构组成，在生长过程中，使用氨气或二甲肼氮作为五族氮源；使用三甲基镓或三乙基镓作为三族镓源，使用三甲基铝或三乙基铝作为三族铝源，使用三甲基铟或三乙基铟作为三族铟源,统称为三族金属源；三甲基铟或三乙基铟也作为表面活性剂，具体包括以下步骤：
（1）沉积非故意掺杂层：使用氢气、氮气或氢氮混合气体作为载流气体，保持五族氮源持续通入，通入三族镓源、三族铝源以及表面活性剂，沉积非故意掺杂层；在沉积该层时，通入三甲基铟或三乙基铟表面活性剂辅助沉积； 
（2）吹扫：使用氢气、氮气或氢氮混合气体作为载流气体，保持五族氮源持续通入，断开三族镓源、三族铝源以及表面活性剂，吹扫已经生长的非故意掺杂层表面，使得表面已沉积的部分三族金属原子发生解吸附，为后续镁掺杂提供更多三族空位；
（3）掺杂：使用氢气、氮气或氢氮混合气体作为载流气体，保持五族氮源持续通入，保持三族镓源、三族铝源以及表面活性剂断开，通入二茂镁受主掺杂剂，使受主掺杂镁原子进入AlGaN半导体材料的晶格中；
（4）镓源通入：使用氢气、氮气或氢氮混合气体作为载流气体，保持二茂镁受主掺杂剂的持续通入，保持五族氮源、三族铝源以及表面活性剂断开，通入三族镓源，增强受主掺杂镁原子在AlGaN半导体材料的晶格中扩散，提高受主并入效率；同时，改善界面两侧AlGaN在界面处的组分变化，增强界面处的能带调制，降低受主激活能；
（5）循环以上四步骤，直至达到所要求生长厚度；
（6）将步骤（5）中达到所要求生长厚度的半导体材料在氮气环境下进行热退火，打断Mg‑H键，激活受主掺杂镁原子，得到p型AlGaN半导体材料。
本发明的p型AlGaN半导体材料生长方法不限于某一类基体材料上生长，其适用范围广泛，其基体材料可以是异质衬底（如：蓝宝石，硅，砷化镓，铝酸锂，镓酸锂，碳化硅或氧化镁等）或同质衬底（三族氮化物，氮化镓，氮化铝等），或者直接在AlGaN上面、n-AlGaN上面或者其他的半导体领域材料层都可以生长。
优选地，所述外延生长方法采用金属有机物化学气相沉积（MOCVD）方法。
优选地，采用表面活性剂辅助delta掺杂方法生长的P型AlGaN半导体材料，其厚度介于100 nm到1000nm之间，其生长温度为800℃～1280℃。
优选地，所述步骤（2）中断开三族镓源、三族铝源以及表面活性剂的时间为15s-45s,所述步骤（3）中通入二茂镁受主掺杂剂的时间为12s-84s，所述步骤（4）中通入三族镓源的时间为3-20s。
优选地，所述步骤（5）中循环以上四步骤10-100周期。
优选地，所述步骤（6）中，退火温度为500℃～980℃，退火时间为30s～3000s。
与现有技术相比，本发明采用表面活性剂辅助delta掺杂生长p型AlGaN半导体材料的方法，具有以下有益效果：
（1）当三甲基铟或三乙基铟作为一种表面活性剂时，会有部分铟原子并入晶格。由于铟-氮键相比于镓-氮键、铝-氮键的键能要小很多，更易从表面解吸附，这种并入-解吸附的动态过程，相当于提高了动态V/III比，起到减少氮空位形成的作用，从而抑制受主掺杂镁原子自补偿效应，增大空穴浓度。
（2）使用三甲基铟或三乙基铟作为表面活性剂后，在delta掺杂工艺中的吹扫阶段，利用铟原子较易解吸附的特点，能够提供更多的晶格空位给受主掺杂镁原子填充，从而增大受主掺杂镁原子的掺入数量，增大受主掺杂镁原子的掺入效率。
（3）采用delta掺杂的工艺方法，降低了受主掺杂镁原子的离化能，使空穴浓度增大。同时，由于三族金属源和二茂镁受主掺杂剂是分开通入反应腔，这种分离的状态可使受主掺杂镁原子正确进入AlGaN半导体材料的晶格，也能起到减少氮空位等缺陷产生的作用，从而抑制受主掺杂镁原子自补偿效应，提高材料的晶体质量，增大空穴浓度；
（4）由于在delta掺杂工艺中的吹扫阶段断开了三族金属源，这一生长中断过程抑制了外延层位错的向上攀升，从而减少了外延层的位错密度，提高材料的晶体质量，减少补偿性缺陷，增大空穴浓度。
特别地，本发明的生长方法加入镓源通入的步骤，具有如下有益效果：
（1）采用在三甲基铟或三乙基铟表面活性剂辅助镁delta掺杂这一方法中，加入“镓源通入”的步骤，在delta掺杂面所进行的镓源补充，使得更多的镓原子并入到前一层，和后一层AlGaN层中，提高掺杂界面两侧AlGaN中的Ga组分，起到降低镁原子的替位形成能的作用，从而提高受主镁原子在上、下AlGaN层中的并入效率；此外，在通入镁源后通入镓源，可以增强镁原子在前一层AlGaN表面的滞留，提高其并入几率。使用该步骤方法后其受主掺杂镁原子的平均浓度从普通传统掺杂的1.1×10 19cm -3提升到了1.6×10 19cm -3以上，涨幅为40%以上，从三甲基铟或三乙基铟表面活性剂辅助镁delta掺杂的1.3×10 19cm -3提升到了1.6×10 19cm -3以上，涨幅为23%以上。
（2）采用在三甲基铟或三乙基铟表面活性剂辅助镁delta掺杂这一方法中，加入“镓源通入”的步骤，镓源的补充，使得Ga原子可以填补因吹扫、delta掺杂步骤所带来的前一层AlGaN表面的三族空位减少缺陷形成，改善了界面粗糙度，减少了其他施主性杂质的并入，同时也可使的Ga更多地并入到后一层生长的AlGaN层中，对delta掺杂界面前、后AlGaN层中的Al组分起到有效的调制作用，增大了Al组分的振荡范围，降低了受主掺杂镁热激活能，提高了受主离化效率，增大空穴浓度；同时，因delta掺杂界面处Al组分变化加剧，使得能带弯曲加大、二维空穴气的浓度提高,空穴浓度从普通传统掺杂的1.59×10 18cm -3提升到了8.2×10 18cm -3以上，提升了4倍以上，从铟表面活性剂辅助镁delta掺杂的4.75×10 18cm -3提升到了8.2×10 18cm -3以上，提升了1.7倍以上。
（3）采用在三甲基铟或三乙基铟表面活性剂辅助镁delta掺杂这一方法中，加入“镓源通入”的步骤，因Ga原子的表面迁移优于Al原子，而使AlGaN在沉积过程中的侧向生长得到增强，外延层受到更大的压应力，外延层向上延伸位错更易产生闭合，从而减少位错密度，提高材料的晶体质量。
（4）本发明的p型AlGaN半导体材料在基体材料上的外延生长方法不限于某一类基体材料，其适用范围广泛，其基体材料可以是异质衬底（如：蓝宝石，硅，砷化镓，铝酸锂，镓酸锂，碳化硅或氧化镁等）或同质衬底（三族氮化物，氮化镓，氮化铝等），或者直接在AlGaN上面、n-AlGaN上面或者其他的半导体材料层上都可以生长。
 有益效果
本发明可改善结晶质量，提高受主掺杂镁原子的掺杂浓度，降低受主离化能，并抑制其自补偿效应，从而获得良好晶体质量以及高空穴浓度的p型AlGaN半导体材料。而且这种外延生长方法不受限于衬底和模板，适用范围广泛；采用本发明提供的外延生长方法生长的p型AlGaN半导体材料其受主掺杂镁原子的平均浓度从普通传统掺杂的1.1×10 19cm -3提升到了1.6×10 19cm -3以上，涨幅为40%以上，从三甲基铟或三乙基铟表面活性剂辅助镁delta掺杂的1.3×10 19cm -3提升到了1.6×10 19cm -3以上，涨幅为23%以上；空穴浓度从普通传统掺杂的1.59×10 18cm -3提升到了8.2×10 18cm -3以上，提升了4倍以上，从铟表面活性剂辅助镁delta掺杂的4.75×10 18cm -3提升到了8.2×10 18cm -3以上，提升了1.7倍以上。
附图说明
图1为本发明的p型AlGaN半导体材料的生长流程示意图；
图2为本发明的p型AlGaN半导体材料的生长时序图；
图3为实施例1-2的p型AlGaN半导体材料的外延生长结构示意图。
 本发明的最佳实施方式
本发明公开的一种p型AlGaN半导体材料生长方法如图1和图2所示，所述半导体材料在基体材料层上采用外延生长方法生长，由不少于一个相同的镁delta掺杂周期结构组成，在生长过程中，使用氨气或二甲肼氮作为五族氮源；使用三甲基镓或三乙基镓作为三族镓源，使用三甲基铝或三乙基铝作为三族铝源, 三甲基铟或三乙基铟作为三族铟源,统称为三族金属源；三甲基铟或三乙基铟也作为表面活性剂，具体包括以下步骤：
（1）沉积非故意掺杂层：使用氢气、氮气或氢氮混合气体作为载流气体，保持五族氮源持续通入，通入三族镓源、三族铝源以及表面活性剂，生长非故意掺杂层；在沉积该层时，通入三甲基铟或三乙基铟表面活性剂辅助沉积； 
（2）吹扫：使用氢气、氮气或氢氮混合气体作为载流气体，保持五族氮源持续通入，断开三族镓源、三族铝源以及表面活性剂，吹扫已经生长的非故意掺杂层表面，使得表面已沉积的部分三族金属原子发生解吸附，为后续镁掺杂提供更多三族空位；
（3）掺杂：使用氢气、氮气或氢氮混合气体作为载流气体，保持五族氮源持续通入，保持三族镓源、三族铝源以及表面活性剂断开，通入二茂镁受主掺杂剂，使受主掺杂镁原子进入AlGaN半导体材料的晶格中；
（4）镓源通入：使用氢气、氮气或氢氮混合气体作为载流气体，保持二茂镁受主掺杂剂的持续通入，保持五族氮源、三族铝源以及表面活性剂断开，通入三族镓源，增强受主掺杂镁原子在AlGaN半导体材料的晶格中扩散，提高受主并入效率；同时，改善界面两侧AlGaN在界面处的组分变化，增强界面处的能带调制，降低受主激活能；
（5）循环以上四步骤，直至达到所要求生长厚度；
（6）将步骤（5）中达到所要求生长厚度的半导体材料在氮气环境下进行热退火，打断Mg‑H键，激活受主掺杂镁原子，得到本发明的p型AlGaN半导体材料。
 本发明的实施方式
下面将通过具体实施例对本发明进行详细说明。
实施例 1 ：
如图3所示，本发明的p型AlGaN半导体材料的外延生长结构包括衬底101、缓冲层或过渡层102、非故意掺杂层103以及受主掺杂层（p型AlGaN半导体材料层）104。所述衬底101是采用蓝宝石衬底，在衬底101上采用金属有机物化学气相沉积(MOCVD)外延生长方法生长出缓冲层102、在缓冲层上采用采用金属有机物化学气相沉积(MOCVD)外延生长方法生长出非故意掺杂AlGaN层103以及在非故意掺杂AlGaN层103上采用金属有机物化学气相沉积(MOCVD)外延生长方法生长出p型AlGaN半导体材料层104。
在本实施案例的生长过程中，使用氨气作为五族氮源；使用三甲基镓作为三族镓源，使用三甲基铝作为三族铝源；三甲基铟作为表面活性剂，在生长p型AlGaN半导体材料层104中使用。实现上述结构具体包含以下四个步骤：
（1）将衬底101置于反应腔内，在衬底101上采用金属有机物化学气相沉积(MOCVD)外延生长方法生长图3所示的外延结构。
（2）缓冲层102为高温生长的非故意掺杂AlN材料，其厚度为300nm。使用氢气作为载流气体，向反应腔内同时通入三族铝源以及五族氮源生长缓冲层102，其生长温度为1160℃。
（3）非故意掺杂AlGaN层103为高温生长的非故意掺杂AlGaN材料，其厚度为500 nm。使用氢气作为载流气体，向反应腔内同时通入三族镓源、三族铝源以及五族氮源生长非故意掺杂AlGaN层103，其生长温度为1160℃。
（4）p型AlGaN半导体材料层104为采用表面活性剂辅助delta掺杂方法生长的p型AlGaN半导体材料，其厚度为500nm，其生长温度为1080℃。所述p型AlGaN半导体材料材料由不少于一个相同的镁delta掺杂周期结构组成，其生长方法具体包含以下六个步骤：
沉积非故意掺杂AlGaN层：使用氢气作为载流气体，保持五族氮源持续通入，通入三族镓源、三族铝源以及三甲基铟表面活性剂，沉积非故意掺杂AlGaN层；
吹扫：使用氢气作为载流气体，保持五族氮源持续通入，断开三族镓源、三族铝源以及表面活性剂30s，吹扫已经生长的非故意掺杂AlGaN层表面，使得表面已沉积的部分三族金属Al、Ga和In原子发生解吸附；
掺杂：使用氢气作为载流气体，保持五族氮源持续通入，保持三族镓源、三族铝源以及表面活性剂断开，通入二茂镁受主掺杂剂48s，使得受主镁原子进入AlGaN的晶格中；
镓源通入：使用氢气作为载流气体，保持二茂镁受主掺杂剂的持续通入，保持五族氮源、三族铝源以及表面活性剂断开，通入三族镓源8s，增强受主掺杂镁原子在AlGaN半导体材料的晶格中扩散，提高受主并入效率；同时，改善界面两侧AlGaN在界面处的组分变化，增强界面处的能带调制，降低受主激活能；
循环以上四步骤，直至达到所要求的生长厚度；
将达到所要求生长厚度的半导体材料在氮气环境下进行热退火，打断Mg‑H键，激活受主掺杂镁原子，退火温度为650℃，退火时间为1500s，得到p型AlGaN半导体材料。
实施例 2 ：
如图3所示，本发明的p型AlGaN半导体材料的外延生长结构包括衬底101、缓冲层或过渡层102、非故意掺杂层103以及受主掺杂层（p型AlGaN半导体材料层）104。所述衬底101采用碳化硅衬底，在衬底101上采用金属有机物化学气相沉积(MOCVD)外延生长方法依次生长出缓冲层102、在缓冲层上采用采用金属有机物化学气相沉积(MOCVD)外延生长方法生长出非故意掺杂AlGaN层103以及在非故意掺杂AlGaN层103上采用金属有机物化学气相沉积(MOCVD)外延生长方法生长出p型AlGaN半导体材料层104。
在本实施案例的生长过程中，使用二甲肼氮作为五族氮源；使用三乙基镓作为三族镓源，使用三乙基铝作为三族铝源；三乙基铟作为表面活性剂，在p型AlGaN半导体材料层中使用。实现该结构具体包含以下六个步骤：
（1）将衬底101置于反应腔内，在衬底101上采用金属有机物化学气相沉积(MOCVD)外延生长方法生长图3所示的外延结构。
（2）缓冲层102为高温生长的非故意掺杂AlN材料，其厚度为500nm。使用氢气作为载流气体，向反应腔内同时通入三族铝源以及五族氮源生长缓冲层102，其生长温度为1180℃。
（3）非故意掺杂AlGaN层103为高温生长的非故意掺杂AlGaN材料，其厚度为500 nm。使用氢气作为载流气体，向反应腔内同时通入三族镓源、三族铝源以及五族氮源生长非故意掺杂AlGaN层103，其生长温度为1180℃。
（4）p型AlGaN半导体材料层为采用表面活性剂辅助delta掺杂方法生长的p型AlGaN半导体材料，其厚度为800nm，其生长温度为1000℃。该生长方法具体包含以下六个步骤：
沉积非故意掺杂AlGaN层：使用氮气作为载流气体，保持五族氮源持续通入，通入三族镓源、三族铝源以及三乙基铟表面活性剂，沉积非故意掺杂AlGaN层；
吹扫：使用氮气作为载流气体，保持五族氮源持续通入，断开三族镓源、三族铝源以及表面活性剂35s，吹扫已经生长的非故意掺杂AlGaN层表面，使得表面已沉积的部分三族金属Al、Ga和In原子发生解吸附；
掺杂：使用氮气作为载流气体，保持五族氮源持续通入，保持三族镓源、三族铝源以及表面活性剂断开，通入二茂镁受主掺杂剂48s，使得受主镁原子进入AlGaN的晶格中；
镓源通入：使用氮气作为载流气体，保持二茂镁受主掺杂剂的持续通入，保持五族氮源、三族铝源以及表面活性剂断开，通入三族镓源10s，增强受主掺杂镁原子在AlGaN半导体材料的晶格中扩散，提高受主并入效率；同时，改善界面两侧AlGaN在界面处的组分变化，增强界面处的能带调制，降低受主激活能；
循环以上四步骤，直至达到所要求的生长厚度；
将达到所要求厚度的半导体材料在氮气环境下进行热退火，打断Mg‑H键，激活受主掺杂镁原子，退火温度为550℃，退火时间为1500s，得到p型AlGaN半导体材料。
实施例 3 ：
本实施例的p型AlGaN半导体材料在AlN材料衬底层上生长，其厚度为500nm，其生长温度为900℃，在本实施案例的生长过程中，使用氨气作为五族氮源；使用三甲基镓作为三族镓源，使用三甲基铝作为三族铝源；三甲基铟作为表面活性剂，具体包括如下步骤：
沉积非故意掺杂AlGaN层：使用氢气作为载流气体，保持五族氮源持续通入，通入三族镓源、三族铝源以及三乙基铟表面活性剂，沉积非故意掺杂AlGaN层；
吹扫：使用氢气作为载流气体，保持五族氮源持续通入，断开三族镓源、三族铝源以及表面活性剂40s，吹扫已经生长的非故意掺杂AlGaN层表面，使得表面已沉积的部分三族金属Al、Ga和In原子发生解吸附；
掺杂：使用氢气作为载流气体，保持五族氮源持续通入，保持三族镓源、三族铝源以及表面活性剂断开，通入二茂镁受主掺杂剂60s，使得受主镁原子进入AlGaN的晶格中；
镓源通入：使用氢气作为载流气体，保持二茂镁受主掺杂剂的持续通入，保持五族氮源、三族铝源以及表面活性剂断开，通入三族镓源8s，增强受主掺杂镁原子在AlGaN半导体材料的晶格中扩散，提高受主并入效率；同时，改善界面两侧AlGaN在界面处的组分变化，增强界面处的能带调制，降低受主激活能；
循环以上四步骤，直至达到所要求的生长厚度；
将达到所要求生长厚度的半导体材料在氮气环境下进行热退火，打断Mg‑H键，激活受主掺杂镁原子，退火温度为550℃，退火时间为1500s，得到本实施例的p型AlGaN半导体材料。
对实施例1-3得到的p型AlGaN半导体材料进行测试，其中实施例1中p型AlGaN半导体材料铝组分含量为42%，受主掺杂镁原子的平均浓度为1.6×10 19cm -3 ，空穴浓度为8.2×10 18cm -3 ，实施例2中p型AlGaN半导体材料铝组分含量为46%,受主掺杂镁原子的平均浓度为1.8×10 19cm -3 ，空穴浓度为8.6×10 18cm -3, 实施例3中p型AlGaN半导体材料铝组分含量为49%，受主掺杂镁原子的平均浓度为2.0×10 19cm -3 ，空穴浓度为8.9×10 18cm -3。
由上可见，本发明的生长方法可改善p型AlGaN半导体材料结晶质量，提高受主掺杂镁原子的掺杂浓度，降低受主离化能，并抑制其自补偿效应，从而获得良好晶体质量以及高空穴浓度的p型AlGaN半导体材料。而且这种外延生长方法不受限于衬底和模板，适用范围广泛；采用本发明提供的外延生长方法生长的p型AlGaN半导体材料，其受主掺杂镁原子的平均浓度从普通传统掺杂的1.1×10 19cm -3提升到了1.6×10 19cm -3以上，涨幅为40%以上，从三甲基铟或三乙基铟表面活性剂辅助镁delta掺杂的1.3×10 19cm -3提升到了1.6×10 19cm -3以上，涨幅为23%以上；空穴浓度从普通传统掺杂的1.59×10 18cm -3提升到了8.2×10 18cm -3以上，提升了4倍以上，从铟表面活性剂辅助镁delta掺杂的4.75×10 18cm -3提升到了8.2×10 18cm -3以上，提升了1.7倍以上，特别是对铝组分含量大于40%的p型AlGaN半导体材料，同样具备以上的技术效果，得到性能优异的半导体材料。
工业实用性
以上所述仅为本发明的较佳实施例，凡依本发明权利要求范围所做的均等变化与修饰，皆应属本发明权利要求的涵盖范围。

Claims (6)

  1. 一种p型AlGaN半导体材料生长方法，其特征在于，所述半导体材料在基体材料层上采用外延生长方法生长，由不少于一个相同的镁delta掺杂周期结构组成，在生长过程中，使用氨气或二甲肼氮作为五族氮源,使用三甲基镓或三乙基镓作为三族镓源，使用三甲基铝或三乙基铝作为三族铝源, 使用三甲基铟或三乙基铟作为三族铟源,统称为三族金属源；三甲基铟或三乙基铟也作为表面活性剂，具体包括以下步骤：
    （1）沉积非故意掺杂层：使用氢气、氮气或氢氮混合气体作为载流气体，保持五族氮源持续通入，通入三族镓源、三族铝源以及表面活性剂，沉积非故意掺杂AlGaN层；在沉积该层时，通入三甲基铟或三乙基铟表面活性剂辅助沉积；
    （2）吹扫：使用氢气、氮气或氢氮混合气体作为载流气体，保持五族氮源持续通入，断开三族镓源、三族铝源以及表面活性剂，吹扫已经生长的非故意掺杂AlGaN层表面，使得表面已沉积的部分三族金属原子发生解吸附；
    （3）掺杂：使用氢气、氮气或氢氮混合气体作为载流气体，保持五族氮源持续通入，保持三族镓源、三族铝源以及表面活性剂断开，通入二茂镁受主掺杂剂，使受主掺杂镁原子进入AlGaN半导体材料的晶格中；
    （4）镓源通入：使用氢气、氮气或氢氮混合气体作为载流气体，保持二茂镁受主掺杂剂的持续通入，保持五族氮源、三族铝源以及表面活性剂断开，通入三族镓源，增强受主掺杂镁原子在AlGaN半导体材料的晶格中扩散；
    （5）循环以上四步骤，直至达到所要求生长厚度；
    （6）将步骤（5）中达到所要求生长厚度的半导体材料在氮气环境下进行热退火，打断Mg‑H键，激活受主掺杂镁原子，得到p型AlGaN半导体材料。
  2. 根据权利要求1所述的p型AlGaN半导体材料生长方法，其特征在于：所述外延生长方法采用金属有机物化学气相沉积方法。
  3. 根据权利要求1所述的p型AlGaN半导体材料生长方法，其特征在于： 所述P型AlGaN半导体材料厚度介于100 nm到1000nm之间，生长温度为800℃～1280℃。
  4. 根据权利要求1所述的p型AlGaN半导体材料生长方法，其特征在于：所述步骤（2）中断开三族镓源、三族铝源以及表面活性剂的时间为15s-45s,所述步骤（3）中通入二茂镁受主掺杂剂的时间为12s-84s，所述步骤（4）中通入三族镓源的时间为3-20s。
  5. 根据权利要求1所述的p型AlGaN半导体材料生长方法，其特征在于：所述步骤（5）中循环以上四步骤10-100周期。
  6. 根据权利要求1所述的p型AlGaN半导体材料生长方法，其特征在于：所述步骤（6）中，退火温度为500℃～980℃，退火时间为30s～3000s。
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102903615A (zh) * 2012-10-18 2013-01-30 中山大学 一种p型GaN与AlGaN半导体材料的制备方法
CN105098001A (zh) * 2014-05-20 2015-11-25 首尔伟傲世有限公司 发光设备及其制造方法
JP2016174071A (ja) * 2015-03-17 2016-09-29 日本電信電話株式会社 結晶成長方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102903615A (zh) * 2012-10-18 2013-01-30 中山大学 一种p型GaN与AlGaN半导体材料的制备方法
CN105098001A (zh) * 2014-05-20 2015-11-25 首尔伟傲世有限公司 发光设备及其制造方法
JP2016174071A (ja) * 2015-03-17 2016-09-29 日本電信電話株式会社 結晶成長方法

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