Method for preparing high electron mobility transistor epitaxial wafer with improved crystal quality

Abstract

The present disclosure provides a method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality, and belongs to the technical field of semiconductor devices. The surface of the AlN layer is subjected to plasma treatment using N2O gas. The surface of the AlN layer is subjected to plasma treatment using positively charged nitrogen atom groups and oxygen atom groups. The positively charged nitrogen atom groups will fill the nitrogen vacancy defects in the negative AlN layer, reducing defects. Negatively charged oxygen atoms are decomposed from the oxide on the surface of the silicon substrate, and are combined with oxygen atoms in the N2O plasma to generate oxygen molecules, reducing impurities. The surface of the AlN layer is subjected to plasma treatment with hydrogen gas, and hydrogen atoms and oxygen atoms are also combined to generate H2O and are discharged from the reaction chamber. The defects and impurities that may exist in the AlN layer are effectively reduced, and the quality of the AlN layer is effectively improved to improve the quality of the high electron mobility transistor finally obtained.

Description

Technical Field

[0001] The present disclosure relates to the technical field of semiconductor devices, and in particular to a method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality. Background Art

[0002] HEMT (High Electron Mobility Transistor) is a heterojunction field effect transistor, which is widely used in various electrical appliances. HEMT epitaxial wafer is the basis for preparing HEMT devices. HEMT epitaxial wafer includes substrate and AlN layer, AlGaN buffer layer, GaN high resistance layer, GaN channel layer, AlGaN barrier layer and GaN cap layer stacked on the substrate in sequence.

[0003] HEMT epitaxial wafers are often grown using silicon substrates as bases. However, on the one hand, oxides similar to silicon oxide are easily present on the surface of the silicon substrate. These oxides are decomposed during the high-temperature epitaxial growth process. The decomposed oxygen atoms will enter the epitaxial material grown on the silicon substrate, and as impurities, affect the quality of the final high electron mobility transistor epitaxial wafer. On the other hand, when the AlN layer is grown on the silicon substrate, the pre-reaction of the Al organic source as the growth source of the AlN layer with ammonia is very serious, and the V / III ratio of the AlN layer growth is low, which will lead to more N vacancy defect states in the AlN layer, resulting in more defects in the obtained high electron mobility transistor. More impurities and defects will affect the quality of the final high electron mobility transistor. Summary of the invention

[0004] The disclosed embodiment provides a method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality, which can effectively reduce impurities and defects inside the high electron mobility transistor to effectively improve the crystal quality of the high electron mobility transistor epitaxial wafer finally obtained. The technical solution is as follows:

[0005] The embodiment of the present disclosure provides a high electron mobility transistor epitaxial wafer, and the method for preparing the high electron mobility transistor epitaxial wafer with improved crystal quality comprises:

[0006] Providing a silicon substrate;

[0007] Growing an AlN layer on the silicon substrate;

[0008] The surface of the AlN layer is subjected to plasma treatment using N2O gas,

[0009] The plasma treatment of the surface of the AlN layer using N2O gas comprises:

[0010] The AlN layer is located at the negative pole of a magnetron sputtering device, and N2O gas is ionized at the positive pole of the magnetron sputtering device to obtain positively charged nitrogen atomic groups and oxygen atomic groups to perform plasma treatment on the surface of the AlN layer;

[0011] Performing plasma treatment on the surface of the AlN layer using hydrogen;

[0012] An AlGaN buffer layer, a GaN high resistance layer, a GaN channel layer, an AlGaN barrier layer and a GaN cap layer are sequentially grown on the surface of the AlN layer.

[0013] Optionally, the flow rate of N2O gas introduced into the sputtering chamber of the magnetron sputtering device is 20-50 sccm.

[0014] Optionally, the surface of the AlN layer is subjected to plasma treatment using N2O gas for 10 to 30 minutes.

[0015] Optionally, the method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality comprises:

[0016] The surface of the AlN layer is subjected to plasma treatment using N2O gas at a temperature of 100-200°C.

[0017] Optionally, under the condition that the sputtering power is 100-500W, N2O gas is used to perform plasma treatment on the surface of the AlN layer.

[0018] Optionally, the plasma treatment of the surface of the AlN layer using hydrogen includes: the flow rate of hydrogen introduced into the sputtering chamber of the magnetron sputtering device is 10-50 sccm.

[0019] Optionally, the method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality further comprises:

[0020] After the surface of the AlN layer is subjected to plasma treatment using hydrogen, the AlN layer is annealed in a nitrogen environment before an AlGaN buffer layer is grown on the surface of the AlN layer.

[0021] Optionally, the AlN layer is annealed in a nitrogen environment at a temperature of 500 to 600° C. for 5 to 10 minutes.

[0022] Optionally, the method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality further comprises:

[0023] After the AlN layer is annealed for 5 to 10 minutes in a nitrogen environment, the temperature of the AlN layer is reduced to 20 to 30° C. in the nitrogen environment.

[0024] Optionally, the annealing treatment of the AlN layer in the nitrogen environment includes:

[0025] During the annealing process of the AlN in a nitrogen environment, 10 to 50 sccm of nitrogen is continuously introduced into the reaction chamber.

[0026] The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure include:

[0027] After growing the AlN layer on the silicon substrate, the surface of the AlN layer is subjected to plasma treatment using N2O gas. The surface of the AlN layer is subjected to plasma treatment using N2O gas, including: placing the AlN layer at the negative pole of the magnetron sputtering device, ionizing the N2O gas at the positive pole of the magnetron sputtering device, obtaining positively charged nitrogen atom groups and oxygen atom groups for plasma treatment of the surface of the AlN layer. The positively charged nitrogen atom groups will fill the nitrogen vacancy defects existing in the negative pole AlN layer due to the growth under the lower V / III ratio conditions, reduce the defects existing in the AlN layer, and improve the crystal quality of the AlN layer. In addition, the negatively charged oxygen atoms decomposed from the oxide on the surface of the silicon substrate move toward the N2O plasma located at the positive pole under the action of the electric field, and combine with the oxygen atoms in the N2O plasma to generate oxygen molecules, thereby reducing the concentration of oxygen atoms existing in the epitaxial layer, reducing the impurities existing in the high electron mobility transistor, so as to improve the crystal quality of the epitaxial layer and the electrical performance of the device. When hydrogen is used to perform plasma treatment on the surface of the AlN layer, the H atoms have a strong etching type and can break the oxygen in the AlN layer that has a strong binding force with Al to form Al-O, thereby separating the oxygen from the AlN layer. In addition, hydrogen atoms and oxygen atoms will also combine to generate H2O and be discharged from the reaction chamber, further reducing the impurities in the AlN layer. The separated oxygen atoms are effectively separated to prevent oxygen from re-entering the epitaxial material and becoming impurities. The defects and impurities in the AlN layer can be effectively reduced, and the quality of the AlN layer can be effectively improved to improve the quality of the high electron mobility transistor obtained in the end. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 It is a flow chart of a method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality provided by an embodiment of the present disclosure;

[0030] Figure 2It is a schematic structural diagram of a high electron mobility transistor epitaxial wafer with improved crystal quality provided by an embodiment of the present disclosure;

[0031] Figure 3 It is a flow chart of another method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality provided by an embodiment of the present disclosure;

[0032] Figure 4 It is a schematic structural diagram of another high electron mobility transistor epitaxial wafer with improved crystal quality provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0034] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons with ordinary skills in the field to which the present disclosure belongs. The words "first", "second", "third" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", "top", "bottom" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0035] Figure 1 This is a flow chart of a method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality provided by an embodiment of the present disclosure, with reference to Figure 1 It can be seen that the embodiment of the present disclosure provides a method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality. The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality includes:

[0036] S101: Provide a silicon substrate.

[0037] S102: growing an AlN layer on a silicon substrate.

[0038] S103: Performing plasma treatment on the surface of the AlN layer using N2O gas. Performing plasma treatment on the surface of the AlN layer using N2O gas includes: placing the AlN layer at the negative pole of a magnetron sputtering device, ionizing the N2O gas at the positive pole of the magnetron sputtering device, obtaining positively charged nitrogen atoms and oxygen atoms to perform plasma treatment on the surface of the AlN layer.

[0039] S104: Plasma treatment is performed on the surface of the AlN layer using hydrogen.

[0040] S105: An AlGaN buffer layer, a GaN high resistance layer, a GaN channel layer, an AlGaN barrier layer and a GaN cap layer are sequentially grown on the surface of the AlN layer.

[0041] After growing the AlN layer on the silicon substrate, the surface of the AlN layer is subjected to plasma treatment using N2O gas. The surface of the AlN layer is subjected to plasma treatment using N2O gas, including: placing the AlN layer at the negative pole of the magnetron sputtering device, ionizing the N2O gas at the positive pole of the magnetron sputtering device, obtaining positively charged nitrogen atom groups and oxygen atom groups for plasma treatment of the surface of the AlN layer. The positively charged nitrogen atom groups will fill the nitrogen vacancy defects existing in the negative pole AlN layer due to the growth under the lower V / III ratio conditions, reduce the defects existing in the AlN layer, and improve the crystal quality of the AlN layer. In addition, the negatively charged oxygen atoms decomposed from the oxide on the surface of the silicon substrate move toward the N2O plasma located at the positive pole under the action of the electric field, and combine with the oxygen atoms in the N2O plasma to generate oxygen molecules, thereby reducing the concentration of oxygen atoms existing in the epitaxial layer, reducing the impurities existing in the high electron mobility transistor, so as to improve the crystal quality of the epitaxial layer and the electrical performance of the device. When hydrogen is used to perform plasma treatment on the surface of the AlN layer, the H atoms have a strong etching type and can break the oxygen in the AlN layer that has a strong binding force with Al to form Al-O, thereby separating the oxygen from the AlN layer. In addition, hydrogen atoms and oxygen atoms will also combine to generate H2O and be discharged from the reaction chamber, further reducing the impurities in the AlN layer. The separated oxygen atoms are effectively separated to prevent oxygen from re-entering the epitaxial material and becoming impurities. The defects and impurities in the AlN layer can be effectively reduced, and the quality of the AlN layer can be effectively improved to improve the quality of the high electron mobility transistor obtained in the end.

[0042] It should be noted that due to the serious pre-reaction of Al and NH3, the viscosity of Al atoms is serious. In order to ensure that the Al atoms are laid evenly in the initial growth of the AlN layer, the growth of the final AlN layer is relatively uniform. When the AlN layer needs to be grown, a lower V / III ratio condition is set to obtain a more uniform AlN layer, and nitrogen vacancy defects in the AlN layer are also generated. The sputtering chamber is a chamber of the magnetron sputtering equipment for placing a silicon substrate, and the reaction chamber is a chamber for placing a silicon substrate and annealing the silicon substrate or growing epitaxial materials on the silicon substrate.

[0043] Optionally, the flow rate of N2O gas introduced into the sputtering chamber of the magnetron sputtering device is 20-50 sccm.

[0044] The flow rate of N2O gas introduced into the sputtering chamber of the magnetron sputtering equipment is within the above range, which can ensure that the N2O gas can stably and effectively ionize oxygen radicals and nitrogen radicals. Sufficient oxygen radicals and nitrogen radicals can remove most of the defects and impurities in the AlN layer, effectively improving the quality of the AlN layer finally obtained. In addition, the flow rate of N2O gas is also relatively reasonable, and there will be no serious reverse reaction of N2O gas, which can ensure stable treatment of the surface of the AlN layer.

[0045] Exemplarily, the surface of the AlN layer is plasma treated using N2O gas for 10 to 30 minutes.

[0046] Using N2O gas to treat the surface of the AlN layer for the above period of time can ensure that the obtained AlN layer has good quality, and can ensure that defects and impurities in the AlN layer are well treated, which can effectively improve the crystal quality of the obtained AlN layer.

[0047] Exemplarily, step S103 includes: performing plasma treatment on the surface of the AlN layer using N2O gas under a sputtering power of 100 to 500W.

[0048] When the sputtering power is within the above range, the stable ionization of the N2O gas can be guaranteed, and the kinetic energy of the atomic groups ionized by the N2O gas is relatively appropriate. When the surface of the AlN layer is processed, the surface of the AlN layer will not be seriously damaged. The defects and impurities in the AlN layer can be effectively reduced while the surface quality of the AlN layer is effectively improved.

[0049] Optionally, step S103 includes: performing plasma treatment on the surface of the AlN layer using N2O gas at a temperature of 100-200°C.

[0050] Treating the AlN layer under the above temperature conditions can ensure that the surface of the AlN layer is effectively and quickly treated, thereby effectively improving the crystal quality of the AlN layer.

[0051] Exemplarily, step S103 includes: performing plasma treatment on the surface of the AlN layer using N2O gas under a pressure of 1 to 10 Torr. The sputtering conditions are relatively reasonable, and the treatment process on the surface of the AlN layer is also relatively mild.

[0052] Optionally, step S104 includes: performing plasma treatment on the surface of the AlN layer using hydrogen, including: the flow rate of hydrogen introduced into the sputtering chamber of the magnetron sputtering equipment is 10-50 sccm.

[0053] The flow rate of the hydrogen gas introduced is within the above range, which can ensure that sufficient hydrogen atoms are ionized and that the hydrogen atoms can effectively etch Al-O to separate oxygen impurities, thereby effectively improving the quality of the AlN layer without excessively increasing the preparation cost of the high electron mobility transistor.

[0054] For example, the sputtering power, temperature, and pressure of the plasma treatment of the surface of the AlN layer by hydrogen gas can be the same as the sputtering power, temperature, and pressure of the plasma treatment of the surface of the AlN layer by N2O gas. This can reduce the preparation cost of the high electron mobility transistor and effectively improve the crystal quality of the AlN layer.

[0055] Figure 2 is a schematic diagram of a structure of a high electron mobility transistor epitaxial wafer with improved crystal quality provided by an embodiment of the present disclosure, with reference to Figure 2 It can be seen that the high electron mobility transistor epitaxial wafer with improved crystal quality includes a silicon substrate 1 and an AlN layer 2, an AlGaN buffer layer 3, a GaN high resistance layer 4, a GaN channel layer 5, an AlGaN barrier layer 6 and a GaN cap layer 7 sequentially stacked on the silicon substrate 1. The basic functions of the epitaxial wafer used to prepare the high electron mobility transistor can be guaranteed.

[0056] Figure 3 is another flow chart of a method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality provided by an embodiment of the present disclosure, with reference to Figure 3 It can be seen that the method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality also includes:

[0057] S201: Provide a silicon substrate.

[0058] Optionally, step S201 includes: treating the surface of the silicon substrate for 5 to 10 minutes under H2 atmosphere, temperature conditions of 1000 to 1200°C, and pressure conditions of 50 to 150 mbar, so as to remove impurities on the surface of the Si-based substrate.

[0059] Exemplarily, step S201 further includes: introducing 50-200 sccm of Al source into the reaction chamber under the conditions of temperature of 1000-1100° C. and pressure of 40-70 mbar to pre-spread a layer of Al atoms on the surface of the silicon substrate, which can promote uniform growth of the AlN layer.

[0060] S202: growing an AlN layer on a silicon substrate.

[0061] Optionally, the growth temperature of the AlN layer is 1050° C. to 1150° C., and the growth pressure of the AlN layer is 40 to 70 mbar, so that a good quality AlN layer can be obtained.

[0062] S203: Performing plasma treatment on the surface of the AlN layer using N2O gas. Performing plasma treatment on the surface of the AlN layer using N2O gas includes: placing the AlN layer at the negative pole of a magnetron sputtering device, ionizing the N2O gas at the positive pole of the magnetron sputtering device, obtaining positively charged nitrogen atoms and oxygen atoms to perform plasma treatment on the surface of the AlN layer.

[0063] S204: Plasma treatment is performed on the surface of the AlN layer using hydrogen.

[0064] Step S203 and step S204 may refer to Figure 1 The steps S103 and S104 are shown in FIG. 1 , and thus are not described in detail here.

[0065] S205: before growing an AlGaN buffer layer on the surface of the AlN layer, annealing the AlN layer in a nitrogen environment.

[0066] The surface of the plasma treated AlN layer is annealed in a nitrogen environment. The AlN layer can be annealed and recrystallized. The surface of the obtained AlN layer will be smoother, and the quality of the epitaxial material grown on the surface of the AlN layer will be improved to improve the quality of the high electron mobility transistor finally obtained.

[0067] Optionally, the AlN layer is annealed for 5 to 10 minutes in a nitrogen environment at a temperature of 500 to 600° C. This ensures that the AlN layer is fully processed and the surface quality of the AlN layer is effectively improved.

[0068] Exemplarily, the method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality further includes:

[0069] After the AlN layer is annealed for 5 to 10 minutes in a nitrogen environment, the temperature of the AlN layer is lowered to 20 to 30° C. in the nitrogen environment. The internal stress of the AlN layer can be released to improve the quality of the obtained AlN layer.

[0070] Optionally, the AlN layer is annealed in a nitrogen environment, including:

[0071] During the annealing process of AlN in a nitrogen environment, 10 to 50 sccm of nitrogen is continuously introduced into the reaction chamber.

[0072] The stability of the gas environment in the reaction chamber can be ensured, and the annealing process of the AlN layer can be prevented from being affected by changes in the gas environment.

[0073] S206: growing an AlGaN buffer layer on the AlN layer.

[0074] Optionally, the growth conditions of the AlGaN buffer layer include: a growth temperature of 1050° C. to 1250° C. and a pressure of 40 to 70 mbar, so that an AlGaN buffer layer of good quality can be obtained.

[0075] S207: growing a GaN high resistance layer on the AlGaN buffer layer.

[0076] The growth conditions and parameters of GaN high resistance layer can be referred to Figure 3 The step S102 shown in FIG. 1 is not described in detail here.

[0077] S208: growing a GaN channel layer on the GaN high resistance layer.

[0078] Optionally, the growth conditions of the GaN channel layer include: a growth temperature of 1050° C. to 1150° C. and a pressure of 150 to 250 mbar, so that a GaN channel layer of good quality can be obtained.

[0079] Exemplarily, the thickness of the GaN channel layer is between 1.0 and 1.5 micrometers, thereby improving the quality of the final HEMT epitaxial wafer and obtaining a GaN channel layer of good quality.

[0080] S209: growing an AlN insertion layer on the GaN channel layer.

[0081] Optionally, the growth temperature of the AlN insertion layer is 1050° C. to 1150° C., and the growth pressure of the AlN insertion layer is 40 to 70 mbar, so that a good quality AlN insertion layer can be obtained.

[0082] S210: growing an AlGaN barrier layer on the AlN insertion layer.

[0083] Optionally, the growth temperature of the AlGaN barrier layer is 1050° C. to 1150° C., and the growth pressure of the AlGaN barrier layer is 40 to 70 mbar. The quality of the obtained AlGaN barrier layer is good.

[0084] In an implementation provided by the present disclosure, the growth temperature of the AlGaN barrier layer may be 1020° C. The present disclosure does not limit this.

[0085] S211: growing a GaN cap layer on the AlGaN barrier layer.

[0086] Optionally, the growth temperature of the GaN cap layer is 1050° C. to 1150° C., and the growth pressure of the AlGaN barrier layer is 40 to 70 mbar. The quality of the obtained GaN cap layer is good.

[0087] It should be noted that in the disclosed embodiment, Veeco K 465i or C4 or RB MOCVD (Metal Organic Chemical Vapor Deposition) equipment is used to realize the growth method of LED. High-purity H2 (hydrogen) or high-purity N2 (nitrogen) or a mixture of high-purity H2 and high-purity N2 is used as a carrier gas, high-purity NH3 is used as an N source, trimethyl gallium (TMGa) and triethyl gallium (TEGa) are used as gallium sources, trimethyl indium (TMIn) is used as an indium source, silane (SiH4) is used as an N-type dopant, trimethyl aluminum (TMAl) is used as an aluminum source, bis(ocene magnesium) (CP2Mg) is used as a P-type dopant, and ferrocene (Cp2Fe) is used as a precursor of an iron (Fe) source.

[0088] Figure 4 is a schematic diagram of the structure of another high electron mobility transistor epitaxial wafer with improved crystal quality provided by an embodiment of the present disclosure, with reference to Figure 4 It can be seen that the high electron mobility transistor epitaxial wafer may include a silicon substrate 1 and an AlN layer 2, an AlGaN buffer layer 3, a GaN high resistance layer 4, a GaN channel layer 5, an AlN insertion layer 8, an AlGaN barrier layer 6 and a GaN cap layer 7 stacked in sequence on the silicon substrate 1.

[0089] Optionally, the thickness of the AlN layer 2 is 150-300 nm, which can ensure that the quality of the AlN layer 2 is good and provide a good growth foundation for the HEMT epitaxial wafer.

[0090] Exemplarily, the thickness of the AlGaN buffer layer 3 is 1 to 1.5 micrometers. The obtained AlGaN buffer layer 3 has good quality.

[0091] Optionally, the thickness of the GaN channel layer 5 may be 100-400 nm.

[0092] The thickness of the GaN channel layer 5 is relatively appropriate, the cost is relatively reasonable, and the quality of the high electron mobility transistor epitaxial wafer can be effectively improved.

[0093] In an implementation provided by the present disclosure, the thickness of the GaN channel layer 5 may be 400 nm, which is not limited by the present disclosure.

[0094] Figure 4 Medium relative Figure 2 In the structure of the HEMT epitaxial wafer, an AlN insertion layer 8 is added. On the one hand, the negative impact caused by the lattice mismatch of the bottom layer is small. On the other hand, the interface where the AlN insertion layer 8 contacts the GaN channel layer 5, and the interface between the AlN insertion layer 8 and the AlGaN barrier layer 6 form a two-dimensional electron gas, which increases the accumulation of carriers at the interface through the two-dimensional electron gas, and can ensure the use effect of the high electron mobility transistor epitaxial wafer.

[0095] Optionally, the thickness of the AlN insertion layer 8 is 0.5-2 nm.

[0096] When the thickness of the AlN insertion layer 8 is within the above range, the two-dimensional electron gas can be effectively generated without excessively increasing the cost.

[0097] In an implementation provided by the present disclosure, the thickness of the AlN insertion layer 8 may be 2 nm, which is not limited by the present disclosure.

[0098] Optionally, the thickness of the AlGaN barrier layer 6 may be 15-40 nm, which can ensure the quality of the high electron mobility transistor epitaxial wafer.

[0099] In an implementation provided by the present disclosure, the thickness of the AlGaN barrier layer 6 may be 100 nm, which is not limited by the present disclosure.

[0100] Exemplarily, the GaN capping layer 7 may be a P-type GaN layer, which is convenient for preparation and acquisition.

[0101] Optionally, the thickness of the GaN capping layer 7 is 3-10 nm. The obtained GaN capping layer 7 has good overall quality.

[0102] Exemplarily, the impurity in the GaN cap layer 7 is Mg, which is convenient for preparation and acquisition.

[0103] It should be noted that Figure 2 This is only one implementation of the high electron mobility transistor epitaxial wafer provided in the embodiment of the present disclosure. In other implementations provided in the present disclosure, the high electron mobility transistor epitaxial wafer may also be other forms of high electron mobility transistor epitaxial wafer including a reflective layer, and the present disclosure does not limit this.

[0104] The above does not limit the present disclosure in any form. Although the present disclosure has been disclosed as above through the embodiments, it is not used to limit the present disclosure. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present disclosure. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present disclosure without departing from the content of the technical solution of the present disclosure still falls within the scope of the technical solution of the present disclosure.

Claims

1. A method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality, characterized in that: The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality comprises: Providing a silicon substrate; Growing an AlN layer on the silicon substrate; The surface of the AlN layer is subjected to plasma treatment using N2O gas, The method of using N2O gas to perform plasma treatment on the surface of the AlN layer comprises: The AlN layer is located at the negative pole of a magnetron sputtering device, and N2O gas is ionized at the positive pole of the magnetron sputtering device to obtain positively charged nitrogen atomic groups and oxygen atomic groups to perform plasma treatment on the surface of the AlN layer; Performing plasma treatment on the surface of the AlN layer using hydrogen; An AlGaN buffer layer, a GaN high resistance layer, a GaN channel layer, an AlGaN barrier layer and a GaN cap layer are sequentially grown on the surface of the AlN layer.

2. The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality according to claim 1, characterized in that: The flow rate of N2O gas introduced into the sputtering chamber of the magnetron sputtering device is 20-50 sccm.

3. The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality according to claim 2, characterized in that: The surface of the AlN layer is subjected to plasma treatment using N2O gas for 10 to 30 minutes.

4. The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality according to any one of claims 1 to 3, characterized in that: The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality comprises: The surface of the AlN layer is subjected to plasma treatment using N2O gas at a temperature of 100-200°C.

5. The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality according to any one of claims 1 to 3, characterized in that: Under the condition that the sputtering power is 100-500W, the surface of the AlN layer is subjected to plasma treatment using N2O gas.

6. The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality according to any one of claims 1 to 3, characterized in that: The plasma treatment of the surface of the AlN layer using hydrogen includes: the flow rate of hydrogen introduced into the sputtering chamber of the magnetron sputtering equipment is 10-50 sccm.

7. The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality according to any one of claims 1 to 3, characterized in that: The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality further comprises: After the surface of the AlN layer is subjected to plasma treatment using hydrogen, the AlN layer is annealed in a nitrogen environment before an AlGaN buffer layer is grown on the surface of the AlN layer.

8. The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality according to claim 7, characterized in that: The AlN layer is annealed for 5 to 10 minutes in a nitrogen environment at a temperature of 500 to 600° C.

9. The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality according to claim 8, characterized in that: The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality further comprises: After the AlN layer is annealed for 5 to 10 minutes in a nitrogen environment, the temperature of the AlN layer is reduced to 20 to 30° C. in the nitrogen environment.

10. The method for preparing a high electron mobility transistor epitaxial wafer with improved crystal quality according to claim 7, characterized in that: Annealing the AlN layer in the nitrogen environment comprises: During the annealing process of the AlN in a nitrogen environment, 10 to 50 sccm of nitrogen is continuously introduced into the reaction chamber.

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