Large-size silicon-based gallium nitride epitaxial device and growth method
By setting up multiple buffer units and stress relief layers in silicon-based gallium nitride epitaxial devices, the problem that existing devices cannot grow thicker buffer layers is solved, and higher voltage resistance and crystallization quality are achieved, which is suitable for high-voltage applications.
Patent Information
- Application Number
- CN202411834248.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-13
- Publication Date
- 2025-03-18
AI Technical Summary
The existing silicon-based gallium nitride epitaxial devices are unable to grow thicker buffer layers, which limit their development in the high voltage field.
The compressive stress and stress relief are prefabricated by stacking a plurality of buffering units and stress relief layers on the silicon substrate, including an AlN nucleation layer, an alternating AlN and AlGaN buffering layer, a low-temperature AlN layer, an AlGaN layer, a first and second GaN layers, a high-carbon doped GaN layer, etc., so as to grow a thicker buffer layer.
It achieves higher voltage resistance and higher quality crystallization, avoids the problem of wafer bending or cracking, and improves the flatness of the device, which is suitable for subsequent chip production.
Smart Images
Figure CN119653841A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor technology, and in particular to a large-size silicon-based gallium nitride epitaxial device and a growth method thereof. Background Art
[0002] As a representative of the third-generation semiconductor materials, gallium nitride materials have the characteristics of wide bandgap, high breakdown electric field and high carrier velocity. AlGaN or GaN HEMT devices, which have been widely developed over the past decades, are particularly superior in high-power microwave applications and have been widely used in many electronic systems in the fields of wireless communications, radar detection, electronic countermeasures, etc.
[0003] Currently, the industry generally adopts heterogeneous substrate epitaxy to grow gallium nitride materials. The most commonly used substrates are silicon, sapphire, silicon carbide and the newly developed diamond; among them, silicon has the largest size, the lowest cost and is conducive to silicon-based monolithic integration.
[0004] Existing silicon-based GaN power devices are limited by the bottleneck of vertical breakdown in the silicon substrate, hindering the development of higher-voltage devices. This is because it is impossible to grow thicker buffer layers, as thicker buffer layers cause stress accumulation, leading to cracking of the epitaxial film. Furthermore, larger substrates increase the difficulty in stress management and the risk of cracking. Summary of the Invention
[0005] In view of the shortcomings of the background technology, the present invention provides a large-size silicon-based gallium nitride epitaxial device and a growth method. The technical problem to be solved is that the existing silicon-based gallium nitride epitaxial devices cannot grow a thicker buffer layer, which limits their development in the high-voltage field.
[0006] To solve the above technical problems, in a first aspect, the present invention provides the following technical solutions: a large-scale silicon-based gallium nitride epitaxial device, comprising a silicon substrate, an AlN nucleation layer, a buffer layer, a stress release layer, a highly carbon-doped GaN layer, a channel layer, a spacer layer, a barrier layer, and a cap layer stacked in sequence from bottom to top;
[0007] The buffer layer includes a plurality of buffer units arranged sequentially from bottom to top, and each buffer unit includes an AlN buffer layer and an AlGaN buffer layer arranged sequentially from bottom to top;
[0008] The stress release layer includes a low-temperature AlN layer, an AlGaN layer, a first GaN layer, and a second GaN layer arranged in sequence from bottom to top; the growth temperature of the first GaN layer is lower than the growth temperature of the second GaN layer.
[0009] In certain embodiments of the first aspect, the size of the silicon substrate is 6 inches, 8 inches, or 12 inches.
[0010] In certain embodiments of the first aspect, the thickness of the AlN nucleation layer is between 150 nm and 250 nm;
[0011] The thickness of the AlN buffer layer is less than that of the AlGaN buffer layer;
[0012] The thickness of the low-temperature AlN layer is between 10nm and 20nm;
[0013] The thickness of the AlGaN layer is between 5nm and 10nm;
[0014] The thickness of the first GaN layer is between 200 nm and 500 nm, and the thickness of the second GaN layer is between 500 nm and 1000 nm;
[0015] The thickness of the highly carbon-doped GaN layer is between 700 nm and 1200 nm;
[0016] The material of the channel layer is GaN, and the thickness is between 200nm and 300nm;
[0017] The spacer layer is made of AlN and has a thickness between 0.5nm and 2nm;
[0018] The barrier layer is made of AlGaN and has a thickness between 20nm and 30nm;
[0019] The capping layer is made of GaN and has a thickness between 2nm and 10nm.
[0020] In certain embodiments of the first aspect, the thickness of the AlN buffer layer is between 10 nm and 20 nm, and the thickness of the AlGaN buffer layer is between 30 nm and 50 nm.
[0021] In a certain embodiment of the first aspect,
[0022] The Al content in the AlGaN layer and the AlGaN buffer layer is between 15% and 45%;
[0023] The Al content in the barrier layer is between 20% and 30%;
[0024] The carbon doping concentration in the highly carbon-doped GaN layer is between 1e19 cm-3 and 3e19 cm-3.
[0025] In certain embodiments of the first aspect, the number of the buffer units is between 50-100.
[0026] In a second aspect, the present invention provides a method for growing a large-size silicon-based gallium nitride epitaxial device, comprising the following steps:
[0027] S1: In an MOCVD reactor, an AlN nucleation layer is formed on a silicon substrate.
[0028] S2: In an MOCVD reactor, alternately growing an AlN buffer layer and an AlGaN buffer layer on the AlN nucleation layer, wherein the number of the AlN buffer layer and the AlGaN buffer layer is the same;
[0029] S3: growing a low-temperature AlN layer on the top AlGaN buffer layer;
[0030] S4: In an MOCVD reactor, an AlGaN layer, a first GaN layer, a second GaN layer, a high carbon-doped GaN layer, a channel layer, a spacer layer, a barrier layer and a cap layer are sequentially grown on the low-temperature AlN layer.
[0031] In certain embodiments of the second aspect, the thickness of the AlN nucleation layer is between 150 nm and 250 nm;
[0032] The thickness of the AlN buffer layer is between 10nm and 20nm, and the thickness of the AlGaN buffer layer is between 30nm and 50nm;
[0033] The thickness of the low-temperature AlN layer is between 10nm and 20nm;
[0034] The thickness of the AlGaN layer is between 5nm and 10nm;
[0035] The thickness of the first GaN layer is between 200 nm and 500 nm, and the thickness of the second GaN layer is between 500 nm and 1000 nm;
[0036] The thickness of the highly carbon-doped GaN layer is between 700 nm and 1200 nm;
[0037] The material of the channel layer is GaN, and the thickness is between 200nm and 300nm;
[0038] The spacer layer is made of AlN and has a thickness between 0.5nm and 2nm;
[0039] The barrier layer is made of AlGaN and has a thickness between 20nm and 30nm;
[0040] The capping layer is made of GaN and has a thickness between 2nm and 10nm.
[0041] In certain embodiments of the second aspect, the Al composition in the AlGaN layer and the AlGaN buffer layer is between 15% and 45%;
[0042] The Al content in the barrier layer is between 20% and 30%;
[0043] The carbon doping concentration in the highly carbon-doped GaN layer is between 1e19 cm-3 and 3e19 cm-3;
[0044] The number of the first GaN layers is between 50 and 100.
[0045] In certain embodiments of the second aspect, the growth temperature of the low-temperature AlN layer is between 700 degrees Celsius and 800 degrees Celsius;
[0046] The growth temperature of the AlGaN layer is between 700 degrees Celsius and 800 degrees Celsius;
[0047] The growth temperature of the first GaN layer is between 800 degrees Celsius and 900 degrees Celsius;
[0048] The growth temperature of the second GaN layer is greater than 900 degrees Celsius and less than or equal to 1000 degrees Celsius.
[0049] Compared with the prior art, the present invention has the following advantages: first, by providing multiple buffer units, each buffer unit includes an AlN buffer layer located below and an AlGaN buffer layer located above. These two layers are grown alternately by setting reasonable thicknesses and matching Al components, which can pre-generate compressive stress to offset the tensile stress caused by the thermal mismatch between the GaN epitaxial layer and the substrate in the cooling stage, thereby avoiding wafer bending or even cracking.
[0050] Secondly, by setting a stress release layer, the excessive stress caused by the excessive thickness of the buffer layer can be alleviated, thereby making a thicker buffer layer and making the device more capable of withstanding voltage.
[0051] In addition, by setting up a stress release layer, the excessive number of defects and dislocations in the buffer layer can be annihilated at the interface, thereby improving the crystal quality of the device.
[0052] Finally, the stress release layer of the present invention is grown by stacking materials with similar lattices, which can obtain a smoother device surface and is beneficial to subsequent chip manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS
[0053] Figure 1 Schematic diagram of the structure of the epitaxial device in Example 1;
[0054] Figure 2 is a flow chart of the growth method in Example 2;
[0055] Figure 3 Schematic diagram of the structure of the buffer unit in the embodiment. DETAILED DESCRIPTION
[0056] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.
[0057] Example 1
[0058] In order to make a thicker buffer layer to improve the voltage resistance of the device, such as Figure 1 As shown, this embodiment provides a large-scale silicon-based gallium nitride epitaxial device, including a silicon substrate 1, an AlN nucleation layer 2, a buffer layer 3, a stress release layer 4, a highly carbon-doped GaN layer 5, a channel layer 6, a spacer layer 7, a barrier layer 8, and a cap layer 9 stacked sequentially from bottom to top;
[0059] The buffer layer 3 includes a plurality of buffer units arranged sequentially from bottom to top, such as Figure 3 As shown, each buffer unit includes an AlN buffer layer 30 and an AlGaN buffer layer 31 arranged from bottom to top; wherein the number of buffer units is between 50 and 100;
[0060] The stress release layer 4 includes a low-temperature AlN layer 40 , an AlGaN layer 41 , a first GaN layer 42 and a second GaN layer 43 arranged in sequence from bottom to top; the growth temperature of the first GaN layer 42 is lower than the growth temperature of the second GaN layer 43 .
[0061] The epitaxial device of the present invention is first provided with multiple buffer units. Each buffer unit includes an AlN buffer layer 30 located below and an AlGaN buffer layer 31 located above. These two layers are grown alternately by setting appropriate thicknesses and matching Al components to pre-generate compressive stress, which is used to offset the tensile stress caused by the thermal mismatch between the GaN epitaxial layer and the substrate during the cooling stage, thereby avoiding wafer bending or even cracking.
[0062] Secondly, by providing the stress release layer 4, the excessive stress generated by the excessive thickness of the buffer layer can be relieved, thereby making it possible to produce a thicker buffer layer 3, thereby making the device more capable of withstanding voltage.
[0063] In addition, by providing the stress release layer 4, the excessive number of defects and dislocations in the buffer layer 3 can be annihilated at the interface, thereby improving the crystal quality of the device;
[0064] Finally, the stress release layer 4 of the present invention is grown by stacking materials with similar lattices, which can obtain a smoother device surface and facilitate subsequent chip manufacturing processes.
[0065] Specifically, in this embodiment, the size of the silicon substrate 1 is 6 inches, 8 inches, or 12 inches.
[0066] In this embodiment, the thickness relationship of the middle layer of the epitaxial device is as follows:
[0067] The thickness of the AlN nucleation layer 2 is between 150 nm and 250 nm;
[0068] In actual use, the AlN nucleation layer 2 of the above thickness can protect the surface of the silicon substrate 1 from being etched by Ga, provide stress support for subsequent epitaxy, and also isolate silicon impurities in the silicon substrate 1 from diffusing into the epitaxial material to a certain extent;
[0069] The thickness of the AlN buffer layer 30 is smaller than that of the AlGaN buffer layer 31 ; wherein the thickness of the AlN buffer layer 30 is between 10 nm and 20 nm, the thickness of the AlGaN buffer layer 31 is between 30 nm and 50 nm, and the Al content in the AlGaN buffer layer 31 is between 15% and 45%;
[0070] In actual use, the AlN buffer layer 30 of the aforementioned thickness and the AlGaN buffer layer 31 of the aforementioned thickness and Al composition can pre-generate compressive stress to offset the tensile stress caused by thermal mismatch during cooling after growth (i.e., to regulate warpage), and can also achieve the device's withstand voltage capability.
[0071] The thickness of the low-temperature AlN layer 40 is between 10 nm and 20 nm;
[0072] The thickness of the AlGaN layer 41 is between 5 nm and 10 nm; the Al content in the AlGaN layer 41 is between 15% and 45%;
[0073] In actual use, the buffer layer 3 and the subsequent first and second GaN layers 42 can be better connected by the low-temperature AlN layer 40 of the aforementioned thickness and the AlGaN layer 41 of the aforementioned thickness and Al composition;
[0074] The thickness of the first GaN layer 42 is between 200 nm and 500 nm, and the thickness of the second GaN layer 42 is between 500 nm and 1000 nm;
[0075] In actual use, the first GaN layer 42 and the second GaN layer 42 of the above thickness can achieve relatively flat GaN layer growth while ensuring the minimum thickness, which is more conducive to the subsequent growth of the high carbon-doped GaN layer 5 and the remaining semiconductor layers;
[0076] The thickness of the high carbon-doped GaN layer 5 is between 700 nm and 1200 nm;
[0077] In actual use, the highly carbon-doped GaN layer 5 of the above thickness can control the warpage of the device;
[0078] The channel layer 6 is made of GaN and has a thickness between 200nm and 300nm.
[0079] The material of the spacer layer 7 is AlN, and the thickness is between 0.5nm and 2nm;
[0080] In actual use, the spacer layer 7 with the above thickness can obtain a lower on-resistance when the device obtains a suitable threshold voltage;
[0081] The barrier layer 8 is made of AlGaN and has a thickness between 20nm and 30nm;
[0082] The cap layer 9 is made of GaN and has a thickness between 2 nm and 10 nm.
[0083] For example, in one embodiment:
[0084] The thickness of the AlN nucleation layer 2 may be 170 nm;
[0085] The thickness of the AlN buffer layer 30 may be 12 nm, and the thickness of the AlGaN buffer layer 31 may be 35 nm;
[0086] The thickness of the low-temperature AlN layer 40 may be 12 nm;
[0087] The thickness of the AlGaN layer 41 may be 7 nm;
[0088] The thickness of the first GaN layer 42 may be 250 nm, and the thickness of the second GaN layer 42 may be 600 nm;
[0089] The thickness of the high carbon-doped GaN layer 5 may be 800 nm;
[0090] The thickness of the channel layer 6 may be 220 nm;
[0091] The thickness of the spacer layer 7 may be 0.8 nm;
[0092] The thickness of the barrier layer 8 may be 22 nm;
[0093] The thickness of the capping layer 9 may be 4 nm.
[0094] For example, in another embodiment:
[0095] The thickness of the AlN nucleation layer 2 may be 230 nm;
[0096] The thickness of the AlN buffer layer 30 may be 18 nm, and the thickness of the AlGaN buffer layer 31 may be 45 nm;
[0097] The thickness of the low-temperature AlN layer 40 may be 16 nm;
[0098] The thickness of the AlGaN layer 41 may be 9 nm;
[0099] The thickness of the first GaN layer 42 may be 400 nm, and the thickness of the second GaN layer 42 may be 800 nm;
[0100] The thickness of the highly carbon-doped GaN layer 5 may be 1000 nm;
[0101] The thickness of the channel layer 6 may be 260 nm;
[0102] The thickness of the spacer layer 7 may be 1.2 nm;
[0103] The thickness of the barrier layer 8 may be 26 nm;
[0104] The thickness of the capping layer 9 may be 8 nm.
[0105] Specifically, in this embodiment, the Al composition in the AlGaN layer 41 and the AlGaN buffer layer 31 may be 20%, 25%, 30% or 35%.
[0106] Specifically, in this embodiment, the Al content in the barrier layer 8 is between 20% and 30%, and may be 22%, 24%, 26% or 28%.
[0107] Specifically, in this embodiment, the carbon doping concentration in the highly carbon-doped GaN layer 5 is between 1e19 cm<-3 > and 3e19 cm<-3 >. In actual use, the above carbon doping concentration can enable the device to achieve better withstand voltage performance.
[0108] The structure of the epitaxial device in this embodiment is analyzed as follows:
[0109] First, since GaN cannot be grown directly on the silicon substrate 1, the AlN nucleation layer 2 prevents Ga from corroding the surface of the silicon substrate 1. Furthermore, the AlN nucleation layer 2 grows very flat, providing a good surface for the growth of subsequent layers and also laying the foundation for the introduction of compressive stress for stress management.
[0110] Second: By setting up alternating distribution of AlN buffer layer 30 and AlGaN buffer layer 31, compressive stress regulation can be introduced to avoid the occurrence of film cracks caused by thermal mismatch in the subsequent GaN cooling stage, which can improve the device's voltage resistance; in addition, during the actual production of the buffer unit, the alternating production of AlN buffer layer 30 and AlGaN buffer layer 31 can be achieved by controlling the opening and closing of the Ga source, which is easy to operate.
[0111] Example 2
[0112] like Figure 2 As shown, this embodiment provides a method for growing a large-size silicon-based gallium nitride epitaxial device, comprising the following steps:
[0113] S1: In an MOCVD reactor, an AlN nucleation layer 2 is formed on a silicon substrate 1 .
[0114] In step S1 , the size of the silicon substrate 1 is 6 inches, 8 inches, or 12 inches.
[0115] S2: In an MOCVD reactor, an AlN buffer layer 30 and an AlGaN buffer layer 31 are alternately grown on the AlN nucleation layer 2 , and the number of the AlN buffer layer 30 and the number of the AlGaN buffer layer 31 are the same;
[0116] S3 : growing a low-temperature AlN layer 40 on the top AlGaN buffer layer 31 .
[0117] In step S3 , a low-temperature AlN layer 40 may be grown on the top AlGaN buffer layer 31 using an MOCVD reactor; or a low-temperature AlN layer 40 may be sputter-grown on the top AlGaN buffer layer 31 using PECVD.
[0118] S4: In an MOCVD reactor, an AlGaN layer 41 , a first GaN layer 42 , a second GaN layer 43 , a high carbon-doped GaN layer 5 , a channel layer 6 , a spacer layer 7 , a barrier layer 8 and a cap layer 9 are sequentially grown on the low-temperature AlN layer 40 .
[0119] Specifically, in this embodiment, the thickness of the AlN nucleation layer 2 is between 150 nm and 250 nm;
[0120] The thickness of the AlN buffer layer 30 is between 10 nm and 20 nm, and the thickness of the AlGaN buffer layer 31 is between 30 nm and 50 nm;
[0121] The thickness of the low-temperature AlN layer 40 is between 10 nm and 20 nm;
[0122] The thickness of the AlGaN layer 41 is between 5 nm and 10 nm;
[0123] The thickness of the first GaN layer 42 is between 200 nm and 500 nm, and the thickness of the second GaN layer 43 is between 500 nm and 1000 nm;
[0124] The thickness of the high carbon-doped GaN layer 5 is between 700 nm and 1200 nm;
[0125] The channel layer 6 is made of GaN and has a thickness between 200nm and 300nm.
[0126] The material of the spacer layer 7 is AlN, and the thickness is between 0.5nm and 2nm;
[0127] The barrier layer 8 is made of AlGaN and has a thickness between 20nm and 30nm;
[0128] The cap layer 9 is made of GaN and has a thickness between 2 nm and 10 nm.
[0129] Specifically, in this embodiment, the Al composition in the AlGaN layer 41 and the AlGaN buffer layer 31 is between 15% and 45%;
[0130] The Al content in the barrier layer 8 is between 20% and 30%;
[0131] The carbon doping concentration in the high carbon-doped GaN layer 5 is between 1e19 cm-3 and 3e19 cm-3;
[0132] The number of the first GaN layers 42 is between 50 and 100.
[0133] Specifically, in this embodiment, the growth temperature of the low-temperature AlN layer 40 is between 700 degrees Celsius and 800 degrees Celsius;
[0134] The growth temperature of the AlGaN layer 41 is between 700 degrees Celsius and 800 degrees Celsius;
[0135] The growth temperature of the first GaN layer 42 is between 800 degrees Celsius and 900 degrees Celsius. In the MOCVD reactor, by setting the growth temperature within this temperature range, the first GaN layer 42 can be grown in a three-dimensional manner.
[0136] The growth temperature of the second GaN layer 43 is greater than 900 degrees Celsius and less than or equal to 1000 degrees Celsius. In the MOCVD reactor, by setting the growth temperature within this temperature range, the second GaN layer 43 can be grown in two or three dimensions.
[0137] The above description is based on the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of this invention. The technical scope of this invention is not limited to the content of the specification, but must be determined according to the scope of the claims.
Claims
1. A large-size silicon-based gallium nitride epitaxial device, characterized in that: It includes a silicon substrate, an AlN nucleation layer, a buffer layer, a stress release layer, a high carbon-doped GaN layer, a channel layer, a spacer layer, a barrier layer and a cap layer stacked in sequence from bottom to top; The buffer layer includes a plurality of buffer units arranged sequentially from bottom to top, and each buffer unit includes an AlN buffer layer and an AlGaN buffer layer arranged sequentially from bottom to top; The stress release layer includes a low-temperature AlN layer, an AlGaN layer, a first GaN layer and a second GaN layer arranged in sequence from bottom to top; the growth temperature of the first GaN layer is lower than the growth temperature of the second GaN layer.
2. A large-size silicon-based gallium nitride epitaxial device according to claim 1, characterized in that: The size of the silicon substrate is 6 inches, 8 inches or 12 inches.
3. A large-size silicon-based gallium nitride epitaxial device according to claim 1, characterized in that: The thickness of the AlN nucleation layer is between 150nm and 250nm; The thickness of the AlN buffer layer is less than that of the AlGaN buffer layer; The thickness of the low temperature AlN layer is between 10nm and 20nm; The thickness of the AlGaN layer is between 5nm and 10nm; The thickness of the first GaN layer is between 200nm and 500nm, and the thickness of the second GaN layer is between 500nm and 1000nm; The thickness of the high carbon-doped GaN layer is between 700nm and 1200nm; The material of the channel layer is GaN, and the thickness is between 200nm and 300nm; The material of the spacer layer is AlN, and the thickness is between 0.5nm and 2nm; The barrier layer is made of AlGaN and has a thickness between 20nm and 30nm; The cap layer is made of GaN and has a thickness between 2nm and 10nm.
4. A large-size silicon-based gallium nitride epitaxial device according to claim 3, characterized in that: The thickness of the AlN buffer layer is between 10nm and 20nm, and the thickness of the AlGaN buffer layer is between 30nm and 50nm.
5. The large-size silicon-based gallium nitride epitaxial device according to claim 3, characterized in that: The Al content in the AlGaN layer and the AlGaN buffer layer is between 15% and 45%; The Al component in the barrier layer is between 20% and 30%; The carbon doping concentration in the high carbon-doped GaN layer is between 1e19 cm-3 and 3e19 cm-3.
6. The large-size silicon-based gallium nitride epitaxial device according to claim 1, characterized in that: The number of the buffer units is between 50 and 100.
7. A method for growing a large-size silicon-based gallium nitride epitaxial device, characterized in that: The following steps are involved: S1: Fabricating an AlN nucleation layer on a silicon substrate in an MOCVD reactor; S2: in an MOCVD reactor, alternately growing an AlN buffer layer and an AlGaN buffer layer on the AlN nucleation layer, wherein the number of the AlN buffer layer and the number of the AlGaN buffer layer are the same; S3: growing a low-temperature AlN layer on the top AlGaN buffer layer; S4: In an MOCVD reactor, an AlGaN layer, a first GaN layer, a second GaN layer, a high carbon-doped GaN layer, a channel layer, a spacer layer, a barrier layer and a cap layer are sequentially grown on the low-temperature AlN layer.
8. The method for growing a large-size silicon-based gallium nitride epitaxial device according to claim 7, characterized in that: The thickness of the AlN nucleation layer is between 150nm and 250nm; The thickness of the AlN buffer layer is between 10nm and 20nm, and the thickness of the AlGaN buffer layer is between 30nm and 50nm; The thickness of the low temperature AlN layer is between 10nm and 20nm; The thickness of the AlGaN layer is between 5nm and 10nm; The thickness of the first GaN layer is between 200nm and 500nm, and the thickness of the second GaN layer is between 500nm and 1000nm; The thickness of the high carbon-doped GaN layer is between 700nm and 1200nm; The material of the channel layer is GaN, and the thickness is between 200nm and 300nm; The material of the spacer layer is AlN, and the thickness is between 0.5nm and 2nm; The barrier layer is made of AlGaN and has a thickness between 20nm and 30nm; The cap layer is made of GaN and has a thickness between 2nm and 10nm.
9. The method for growing a large-size silicon-based gallium nitride epitaxial device according to claim 8, characterized in that: The Al content in the AlGaN layer and the AlGaN buffer layer is between 15% and 45%; The Al component in the barrier layer is between 20% and 30%; The carbon doping concentration in the high carbon-doped GaN layer is between 1e19 cm-3 and 3e19 cm-3; The number of the first GaN layers is between 50 and 100.
10. A method for growing a large-size silicon-based gallium nitride epitaxial device according to claim 8 or 9, characterized in that: The growth temperature of the low temperature AlN layer is between 700 degrees Celsius and 800 degrees Celsius; The growth temperature of the AlGaN layer is between 700 degrees Celsius and 800 degrees Celsius; The growth temperature of the first GaN layer is between 800 degrees Celsius and 900 degrees Celsius; The growth temperature of the second GaN layer is greater than 900 degrees Celsius and less than or equal to 1000 degrees Celsius.