Epitaxial AlGaN / GaN heterojunction device based on Si substrate and preparation method of epitaxial AlGaN / GaN heterojunction device

Abstract

The invention discloses an epitaxial AlGaN / GaN heterojunction device based on a Si substrate and a preparation method thereof, the epitaxial AlGaN / GaN heterojunction device comprises a substrate, ions are injected into the substrate, and the first surface of the substrate is in a concave-convex shape; the nucleating layer is located on the first surface of the substrate, and the surface, making contact with the substrate, of the nucleating layer is in a concave-convex shape and is matched with the first surface of the substrate; the first superlattice layer is located on the surface, away from the substrate, of the nucleating layer, and the first buffer layer is located on the surface, away from the substrate, of the first superlattice layer; the second superlattice layer is located on the surface, away from the substrate, of the buffer layer; the second buffer layer is located on the surface, away from the substrate, of the second superlattice layer; the channel layer is located on the surface, away from the substrate, of the second buffer layer; the insertion layer is located on the surface, away from the substrate, of the channel layer; the barrier layer is located on the surface, away from the substrate, of the insertion layer; the cap layer is located on the surface, away from the substrate, of the barrier layer. The performance index of the device can be improved.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and particularly relates to an AlGaN / GaN heterojunction device epitaxially grown on a Si substrate and a preparation method thereof. Background Art

[0002] As a representative of wide-bandgap power semiconductor devices, gallium nitride-based high electron mobility transistors (GaN HEMTs) have great potential in high-frequency power applications. Compared with Si and SiC, GaN materials have higher electron mobility, saturated electron velocity, and breakdown electric field. Thanks to these material properties, GaN power devices are more suitable for high-frequency and power applications, which is very beneficial to improving the efficiency and power density of converters.

[0003] However, due to the limitations of GaN material growth technology, the current traditional method is still heteroepitaxy. The heteroepitaxy of Si-based GaN will result in a larger defect and dislocation density due to lattice mismatch and differences in thermal expansion coefficients, thereby reducing the material performance index and damaging the reliability of the device.

[0004] The GaN preparation process on a Si substrate in the prior art has two inevitable problems: one is that due to the existence of the heterojunction, a high density of dislocations is generated in GaN. The high density of dislocations will become a current leakage path, damaging the reliability of the device and hindering the further improvement of device performance. The other is that in the Si-based GaN epitaxial layer, there is a p-type conductive channel at the AlN / Si interface, which is caused by the diffusion doping of Al and Ga atoms in the epitaxial layer into the Si substrate. This will introduce a relatively high radio frequency loss to the Si-based GaN material and reduce the frequency performance of the Si-based GaN radio frequency device.

[0005] In summary, due to the inability of the Si-based GaN epitaxial process in the prior art to meet the requirements of low defects and high crystal quality, the development and application of GaN-based HEMT power devices are restricted. There is an urgent need for an epitaxial technology that can effectively improve the epitaxial quality of Si-based GaN materials and suppress the problem of substrate radio frequency loss. Summary of the Invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides an AlGaN / GaN heterojunction device epitaxially grown on a Si substrate and a preparation method thereof. The technical problems to be solved by the present invention are realized through the following technical solutions:

[0007] In a first aspect, the present invention provides an AlGaN / GaN heterojunction device epitaxially grown on a Si substrate, including:

[0008] A substrate, with ions implanted therein, and the first surface of the substrate is concave-convex.

[0009] The nucleation layer is located on the first surface of the substrate, and the surface of the nucleation layer in contact with the substrate is uneven and fits the first surface of the substrate;

[0010] The first superlattice layer is located on the surface of the nucleation layer facing away from the substrate;

[0011] The first buffer layer is located on the surface of the first superlattice layer facing away from the substrate;

[0012] The second superlattice layer is located on the surface of the buffer layer facing away from the substrate;

[0013] The second buffer layer is located on the surface of the second superlattice layer facing away from the substrate;

[0014] The channel layer is located on the surface of the second buffer layer facing away from the substrate;

[0015] The insertion layer is located on the surface of the channel layer facing away from the substrate;

[0016] The barrier layer is located on the surface of the insertion layer facing away from the substrate;

[0017] The cap layer is located on the surface of the barrier layer facing away from the substrate.

[0018] In a second aspect, the present invention further provides a method for preparing an epitaxial AlGaN / GaN heterojunction device on a Si substrate, which is used to prepare the above-mentioned epitaxial AlGaN / GaN heterojunction device on a Si substrate, and includes:

[0019] Provide a substrate, pattern the first surface of the substrate so that the first surface of the substrate is uneven, and perform ion implantation on the first surface of the substrate;

[0020] Grow a nucleation layer on the first surface of the substrate;

[0021] Grow a first superlattice layer on the surface of the nucleation layer;

[0022] Grow a first buffer layer on the surface of the first superlattice layer;

[0023] Grow a second superlattice layer on the surface of the first buffer layer;

[0024] Grow a second buffer layer on the surface of the second superlattice layer;

[0025] Grow a channel layer on the surface of the second buffer layer;

[0026] Grow an insertion layer on the surface of the channel layer;

[0027] Grow a barrier layer on the surface of the insertion layer;

[0028] Grow a cap layer on the surface of the barrier layer.

[0029] Advantages of the present invention:

[0030] A kind of AlGaN / GaN heterojunction device epitaxially grown on a Si substrate and a preparation method provided by the present invention. By means of patterning the substrate and implanting ions into the substrate, the way of ion implantation-induced nucleation combination is adopted, and multiple superlattice layers and multiple buffer layers are used; it can reduce the defect and dislocation density of the epitaxial material, improve the crystal quality of the heterojunction, inhibit the radio frequency loss of the substrate, and improve the performance indexes of the heterojunction and the device.

[0031] The following will further elaborate on the present invention in conjunction with the drawings and embodiments. Description of the Drawings

[0032] Figure 1 is a schematic diagram of a kind of AlGaN / GaN heterojunction device epitaxially grown on a Si substrate provided by an embodiment of the present invention;

[0033] Figure 2 is a flowchart of a preparation method of an AlGaN / GaN heterojunction device epitaxially grown on a Si substrate provided by an embodiment of the present invention;

[0034] Figures 3a to 3l is another flowchart of a preparation method of an AlGaN / GaN heterojunction device epitaxially grown on a Si substrate provided by an embodiment of the present invention. Detailed Embodiments

[0035] The following further describes the present invention in detail with specific embodiments, but the implementation manners of the present invention are not limited thereto.

[0036] Please refer to Figure 1 , Figure 1 is a schematic diagram of a kind of AlGaN / GaN heterojunction device epitaxially grown on a Si substrate provided by an embodiment of the present invention. A kind of AlGaN / GaN heterojunction device provided by the present invention includes:

[0037] A substrate 10, ions are implanted into the substrate 10, and the first surface of the substrate 10 is concave-convex;

[0038] A nucleation layer 20, located on the first surface of the substrate 10, and the surface of the nucleation layer 20 in contact with the substrate 10 is concave-convex and fits with the first surface of the substrate 10;

[0039] A first superlattice layer 30, located on the surface of the nucleation layer 20 facing away from the substrate 10,

[0040] A first buffer layer 40, located on the surface of the first superlattice layer 30 facing away from the substrate 10;

[0041] A second superlattice layer 50, located on the surface of the buffer layer facing away from the substrate 10;

[0042] The second buffer layer 60 is located on the surface of the second superlattice layer 50 facing away from the substrate 10;

[0043] The channel layer 70 is located on the surface of the second buffer layer 60 facing away from the substrate 10;

[0044] The insertion layer 80 is located on the surface of the channel layer 70 facing away from the substrate 10;

[0045] The barrier layer 90 is located on the surface of the insertion layer 80 facing away from the substrate 10;

[0046] The cap layer 100 is located on the surface of the barrier layer 90 facing away from the substrate 10.

[0047] Specifically, please continue to refer to Figure 1 , for the AlGaN / GaN heterojunction device epitaxially grown on the Si substrate provided in this embodiment, by means of patterning the substrate 10 and implanting ions into the substrate 10, the ion implantation-induced nucleation combination method, and adopting a multi-layer superlattice layer and a multi-layer buffer layer; the defects and dislocation density of the epitaxial material can be reduced, the crystal quality of the heterojunction can be improved, the radio frequency loss of the substrate 10 can be inhibited, and the performance indexes of the heterojunction and the device can be improved.

[0048] In an alternative embodiment of the present invention, the material of the substrate 10 is Si, and the ions implanted into the substrate 10 are P ions.

[0049] Specifically, in this embodiment, on the one hand, a patterned substrate 10 is adopted, and the first surface of the substrate 10 is concave-convex, both the concave shape and the convex shape are trapezoidal. A nucleation layer 20 is grown on the first surface of the substrate 10, so that the dislocations of the nucleation layer 20 material will extend upward to the surface of the epitaxial layer. However, for the material grown on the side surface of the substrate 10 pattern, the dislocation direction bends by 90°, so that the dislocation line will not reach the surface of the epitaxial layer, thereby effectively reducing the dislocation density on the surface of the GaN epitaxial layer. On the other hand, a Si substrate implanted with low-energy and low-dose ions is adopted. Compared with the conventional Si substrate, the implanted substrate provides more high-density dangling bonds during the subsequent epitaxial growth process. The high-quality induced nucleation induced by ion implantation dominates, which can provide more dangling bonds and improve the crystal quality of the heterojunction. Moreover, the P ions implanted play a compensating role for the p-type conductive channel at the interface between the Si substrate and AlN, inhibiting the radio frequency loss.

[0050] In an alternative embodiment of the present invention, the thickness of the nucleation layer 20 is 170 - 220 nm, and the material of the nucleation layer 20 is AlN

[0051] In an alternative embodiment of the present invention, the thickness of the first superlattice layer 30 is 400 - 480 nm, and the material of the first superlattice layer 30 is AlN / Al xGa 1-x The adjustment range of the N and Al content is 0.7 to 0.75.

[0052] In an alternative embodiment of the present invention, the thickness of the first buffer layer 40 is 1000 to 1200 nm, and the material of the first buffer layer 40 is Al x Ga 1-x The adjustment range of the N and Al content is 0.3 to 0.4.

[0053] In an alternative embodiment of the present invention, the thickness of the second superlattice layer 50 is 1170 to 1280 nm, and the material of the second superlattice layer 50 is AlN / GaN.

[0054] In an alternative embodiment of the present invention, the thickness of the second buffer layer 60 is 2200 to 2300 nm, and the material of the second buffer layer 60 is GaN.

[0055] In an alternative embodiment of the present invention, the thickness of the channel layer 70 is 300 to 400 nm, and the material of the channel layer 70 is GaN.

[0056] In an alternative embodiment of the present invention, the thickness of the insertion layer 80 is 1 to 2 nm, and the material of the insertion layer 80 is AlN.

[0057] In an alternative embodiment of the present invention, the thickness of the barrier layer 90 is 20 to 40 nm, and the material of the barrier layer 90 is Al x Ga 1-x The adjustment range of the N and Al content is 0.2 to 0.3.

[0058] In an alternative embodiment of the present invention, the thickness of the cap layer 100 is 2 to 4 nm, and the material of the cap layer 100 is GaN.

[0059] Based on the same inventive concept, please refer to Figure 2 , Figure 2 is a flowchart of a method for fabricating an AlGaN / GaN heterojunction device epitaxially grown on a Si substrate provided by an embodiment of the present invention. The present invention also provides a method for fabricating an AlGaN / GaN heterojunction device epitaxially grown on a Si substrate for fabricating the device provided by the above embodiment of the present invention. For the fabrication method of the device, please refer to the above, and details are not described herein again; the fabrication method includes:

[0060] S101, providing a substrate 10, patterning the first surface of the substrate 10 so that the first surface of the substrate 10 is concave and convex, and performing ion implantation on the first surface of the substrate 10;

[0061] S102. Grow a nucleation layer 20 on the first surface of the substrate 10 to provide nucleation sites for subsequent epitaxial layers and improve the crystal quality of the GaN epitaxial layer.

[0062] S103. Grow a first superlattice layer 30 on the surface of the nucleation layer 20 to relieve stress caused by lattice constant mismatch and reduce defects.

[0063] S104. Grow a first buffer layer 40 on the surface of the first superlattice layer 30 to improve the nucleation quality.

[0064] S105. Grow a second superlattice layer 50 on the surface of the first buffer layer 40 to reduce material defects and dislocations.

[0065] S106. Grow a second buffer layer 60 on the surface of the second superlattice layer 50 to reduce the dislocation density.

[0066] S107. Grow a channel layer 70 on the surface of the second buffer layer 60.

[0067] S108. Grow an insertion layer 80 on the surface of the channel layer 70.

[0068] S109. Grow a barrier layer 90 on the surface of the insertion layer 80 to complete the main structure of the epitaxial heterojunction.

[0069] S1010. Grow a cap layer 100 on the surface of the barrier layer 90 to serve as a passivation layer and reduce the gate leakage current.

[0070] In an optional embodiment of the present invention, the first surface of the substrate 10 is patterned so that the first surface of the substrate 10 is concave-convex, including:

[0071] Coat a photoresist on the first surface of the substrate 10, and perform drying, exposure, and development.

[0072] Perform ion etching on the surface of the substrate 10 coated with the photoresist, and remove the remaining photoresist on the substrate 10, so that the first surface of the substrate 10 is concave-convex, and both the concave and convex shapes are trapezoidal.

[0073] In an optional embodiment of the present invention, ion implantation is performed on the first surface of the substrate 10, including:

[0074] Place the substrate 10 in an ion implantation device, perform P ion implantation on the first surface of the substrate 10, with an implantation concentration of 1×10 11 ~5×10 11 cm -2 , an implantation energy of 28 - 32 keV, and an implantation angle of 6 - 8° with respect to the first surface of the substrate 10 to improve the nucleation ability of the substrate 10.

[0075] After the injection is completed, place the substrate 10 in an acetone solution and ultrasonically clean it for 18 - 22 min;

[0076] Place the cleaned substrate 10 in a drying oven and dry it at 65 - 75 °C, then soak it in a 10 - 20% dilute hydrochloric acid solution for 55 - 65 s. After that, place the soaked substrate 10 in the drying oven and dry it at 125 - 135 °C.

[0077] In an alternative embodiment of the present invention, growing a nucleation layer 20 on the first surface of the substrate 10 includes:

[0078] Using metal - organic chemical vapor deposition process, grow a nucleation layer 20 on the first surface of the substrate 10. The thickness of the nucleation layer 20 is 170 - 220 nm, and the material of the nucleation layer 20 is AlN.

[0079] In an alternative embodiment of the present invention, growing a first superlattice layer 30 on the surface of the nucleation layer 20 includes:

[0080] Using metal - organic chemical vapor deposition process, grow 40 - 45 superlattice periodic structures on the surface of the nucleation layer 20 to obtain a first superlattice layer 30 with a thickness of 400 - 480 nm. The material of the first superlattice layer 30 is AlN / Al x Ga 1-x N, and the adjustment range of the Al content is 0.7 - 0.75.

[0081] In an alternative embodiment of the present invention, growing a first buffer layer 40 on the surface of the first superlattice layer 30 includes:

[0082] Using metal - organic chemical vapor deposition process, grow a first buffer layer 40 on the surface of the first superlattice layer 30. The thickness of the first buffer layer 40 is 1000 - 1200 nm, and the material of the first buffer layer 40 is Al x Ga 1-x N, and the adjustment range of the Al content is 0.3 - 0.4.

[0083] In an alternative embodiment of the present invention, growing a second superlattice layer 50 on the surface of the first buffer layer 40 includes:

[0084] Using metal - organic chemical vapor deposition process, grow 47 - 50 superlattice periodic structures on the surface of the first buffer layer 40 to obtain a second superlattice layer 50 with a thickness of 1170 - 1280 nm. The material of the second superlattice layer 50 is AlN / GaN.

[0085] In an alternative embodiment of the present invention, growing a second buffer layer 60 on the surface of the second superlattice layer 50 includes:

[0086] Using metal-organic chemical vapor deposition process, a second buffer layer 60 is grown on the surface of the second superlattice layer 50. The thickness of the second buffer layer 60 is 2200 - 2300 nm, and the material of the second buffer layer 60 is GaN.

[0087] In summary, for a method for preparing an AlGaN / GaN heterojunction device epitaxially grown on an Si substrate provided by the present invention, on the one hand, a patterned substrate 10 is used, and the first surface of the substrate 10 is concave-convex, with both the concave and convex shapes being trapezoidal. A nucleation layer 20 is grown on the first surface of the substrate 10, such that the dislocations of the nucleation layer 20 material will extend upward to the surface of the epitaxial layer. However, for the material grown on the side surface of the pattern of the substrate 10, the dislocation direction bends by 90°, so the dislocation lines will not reach the surface of the epitaxial layer, thereby effectively reducing the dislocation density on the surface of the GaN epitaxial layer. On the other hand, an Si substrate subjected to low-energy and low-dose ion implantation is used. Compared with a conventional Si substrate, the implanted substrate 10 provides more high-density dangling bonds during the subsequent epitaxial growth process. The high-quality induced nucleation induced by ion implantation dominates, which can provide more dangling bonds and improve the crystal quality of the heterojunction. Moreover, the P ions implanted play a compensating role in the p-type conductive channel at the interface between the Si substrate and AlN, suppressing the radio frequency loss.

[0088] In an optional embodiment of the present invention, please refer to FIG. 3. FIG. 3 is another flowchart of the method for preparing an AlGaN / GaN heterojunction device epitaxially grown on an Si substrate provided by the embodiment of the present invention. The device is prepared through the following process, specifically:

[0089] S1. Provide a substrate 10, and the substrate 10 is an Si substrate, as Figure 3a shown.

[0090] S2. Perform patterning and cleaning on the substrate 10, as Figure 3b shown.

[0091] First, clean the Si substrate and bake it at 200 °C for more than 30 minutes to remove surface water molecules; then, coat the Microchem SU-8 2150 epoxy photoresist on the first surface of the substrate 10, and perform drying, exposure, and development; finally, perform RIE reactive ion etching on the substrate 10 wafer, and then remove the excess photoresist on the surface through a remover to complete the preparation process of the trapezoidal patterned Si substrate.

[0092] S3. Perform ion implantation on the substrate 10, as Figure 3c shown.

[0093] Place the Si substrate into the ion implantation equipment cavity for P ion implantation, and the implantation concentration is 1×1011 cm -2 The implantation energy is 30 keV, and the implantation angle forms an incident angle of 7° with the first surface of the substrate 10. The implanted substrate 10 is placed in a container filled with acetone solution and then put into an ultrasonic cleaning device for 20 min. After that, the cleaned substrate 10 is taken out and put into a drying oven for drying at a temperature of 70 °C. Then the substrate 10 is immersed in a 10% dilute hydrochloric acid solution for 60 s. After that, the immersed substrate 10 is taken out and put into a drying oven for drying again at a temperature of 130 °C.

[0094] S4. Prepare the AlN nucleation layer 20, as Figure 3d shown.

[0095] On the treated substrate 10, a metalorganic chemical vapor deposition (MOCVD) process is used. The pressure in the reaction chamber is 100 mbar. TMAl is introduced for the pre-aluminum deposition process with a flow rate of 20 sccm. Subsequently, the temperature is reduced to 900 °C, and NH3 is introduced for the growth of low-temperature AlN. The growth time is 4 min, the flow rate of the TMAl source is 260 sccm, and the flow rate of NH3 is 4000 sccm. The thickness of the grown low-temperature AlN is 30 nm. After the growth of the low-temperature AlN nucleation layer 20 is completed, the temperature of the reaction chamber is increased to 1210 °C to grow a 170-nm-thick high-temperature AlN nucleation layer 20. The flow rates of the TMAl source and NH3 used are 190 sccm and 1500 sccm respectively, and the growth time is 35 min.

[0096] S5. Prepare the AlN / Al x Ga 1-x N superlattice layer, as Figure 3e shown.

[0097] Control the temperature of the reaction chamber to be 1040 °C, the pressure in the reaction chamber to be 200 mbar, and introduce NH3, TMGa, and TMAl. The flow rate of NH3 is 50000 sccm, the flow rate of TMGa is 10 sccm, and the flow rate of TMAl is 180 sccm. Grow 45 superlattice period structures to obtain a superlattice layer with a thickness of 450 nm, and form a superlattice layer on the AlN nucleation layer 20 to complete the preparation of the AlN / Al 0.7 Ga 0.3 N heterojunction.

[0098] S6. Prepare the Al x Ga 1-x N buffer layer, as Figure 3f shown.

[0099] Set the temperature of the reaction chamber to 1050 °C and the pressure of the reaction chamber to 80 mbar. Simultaneously introduce three gases into the reaction chamber: ammonia with a flow rate of 5000 sccm, a gallium source with a flow rate of 30 sccm, and an aluminum source with a flow rate of 150 sccm. On the AlN / Al x Ga 1-x N superlattice layer, grow Al with a thickness of 1100 nm 0.35 Ga 0.65 N to complete the preparation of the Al 0.35 Ga 0.65 N buffer layer.

[0100] S7. Prepare the AlN / GaN superlattice layer, as shown in Figure 3g shown.

[0101] Adjust the temperature of the reaction chamber to 1050 °C. Simultaneously introduce ammonia with a flow rate of 5000 sccm, a gallium source with a flow rate of 60 sccm, and an aluminum source with a flow rate of 120 sccm. Under the condition of maintaining a pressure of 50 mbar, grow 48 superlattice period structures and grow an AlN / GaN superlattice layer with a thickness of 1750 nm.

[0102] S8. Prepare the GaN buffer layer, as shown in Figure 3h shown.

[0103] After the preparation of the AlN / GaN superlattice layer is completed, set the temperature of the reaction chamber to 1100 °C and the pressure of the reaction chamber to 100 mbar. Simultaneously introduce two gases into the reaction chamber: ammonia with a flow rate of 6000 sccm and TMGa with a flow rate of 150 sccm. On the AlN / GaN superlattice layer, grow a GaN buffer layer with a thickness of 2200 nm.

[0104] S9. Prepare the GaN channel layer 70, as shown in Figure 3i shown.

[0105] After the preparation of the GaN buffer layer is completed, in the reaction chamber of the MOCVD equipment, set the temperature of the reaction chamber to 1100 °C and the pressure of the reaction chamber to 100 mbar. Simultaneously introduce two gases into the reaction chamber: ammonia with a flow rate of 6000 sccm and TMGa with a flow rate of 150 sccm. On the GaN buffer layer, grow a GaN channel layer 70 with a thickness of 350 nm.

[0106] S10. Prepare the AlN insertion layer 80, as shown in Figure 3j shown.

[0107] Set the temperature of the reaction chamber to 1020 °C, the pressure of the reaction chamber to 50 mbar, and simultaneously introduce two gases, ammonia with a flow rate of 4000 sccm and an aluminum source with a flow rate of 80 sccm, into the reaction chamber to grow an AlN insertion layer 80 with a thickness of 1 nm on the GaN barrier layer 90.

[0108] S11. Prepare the Al x Ga 1-x N barrier layer 90, as Figure 3k shown.

[0109] Set the temperature of the reaction chamber to 1040 °C, the pressure of the reaction chamber to 50 mbar, and simultaneously introduce three gases, ammonia with a flow rate of 5000 sccm, a gallium source with a flow rate of 120 sccm, and an aluminum source with a flow rate of 30 sccm, into the reaction chamber to grow Al 0.25 Ga 0.75 N with a thickness of 30 nm on the AlN spacer layer to complete the preparation of the Al 0.25 Ga 0.75 N / GaN heterojunction.

[0110] S12. Prepare the GaN cap layer 100, as Figure 3l shown.

[0111] Set the temperature of the reaction chamber to 1040 °C, the pressure of the reaction chamber to 50 mbar, and simultaneously introduce two gases, ammonia with a flow rate of 5000 sccm and a gallium source with a flow rate of 150 sccm, into the reaction chamber to grow a GaN cap layer 100 with a thickness of 2 nm on the Al 0.25 Ga 0.75 N barrier layer 90.

[0112] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant are intended to cover non-exclusive inclusion, so that an article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the article or device comprising said element. Similar words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The orientation or positional relationship indicated by "above", "below", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present invention.

[0113] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0114] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. An AlGaN / GaN heterojunction device based on epitaxial growth on a Si substrate, characterized in that: include: A substrate, into which ions are implanted, and a first surface of the substrate is concavoconvex; A nucleation layer is located on the first surface of the substrate, and the surface of the nucleation layer in contact with the substrate is concave-convex and fits with the first surface of the substrate; A first superlattice layer is located on a surface of the nucleation layer facing away from the substrate; A first buffer layer, located on a surface of the first superlattice layer facing away from the substrate; A second superlattice layer is located on a surface of the buffer layer facing away from the substrate; a second buffer layer, located on a surface of the second superlattice layer facing away from the substrate; a channel layer, located on a surface of the second buffer layer facing away from the substrate; an insertion layer, located on a surface of the channel layer facing away from the substrate; A barrier layer, located on a surface of the insertion layer facing away from the substrate; The cap layer is located on the surface of the barrier layer facing away from the substrate.

2. The AlGaN / GaN heterojunction device based on epitaxial growth on Si substrate according to claim 1, characterized in that: The material of the substrate is Si, and the ions implanted into the substrate are P ions.

3. A method for preparing an epitaxial AlGaN / GaN heterojunction device on a Si substrate, for preparing an epitaxial AlGaN / GaN heterojunction device on a Si substrate as claimed in any one of claims 1 to 2, characterized in that: include: Providing a substrate, patterning a first surface of the substrate so that the first surface of the substrate is concave-convex, and performing ion implantation on the first surface of the substrate; growing a nucleation layer on a first surface of the substrate; growing a first superlattice layer on the surface of the nucleation layer; growing a first buffer layer on a surface of the first superlattice layer; growing a second superlattice layer on a surface of the first buffer layer; growing a second buffer layer on a surface of the second superlattice layer; growing a channel layer on a surface of the second buffer layer; growing an insertion layer on a surface of the channel layer; growing a barrier layer on a surface of the insertion layer; A cap layer is grown on the surface of the barrier layer.

4. The method for preparing an epitaxial AlGaN / GaN heterojunction device on a Si substrate according to claim 3, characterized in that: Patterning the first surface of the substrate so that the first surface of the substrate is concave-convex, comprising: Coating a photoresist on the first surface of the substrate, and performing drying, exposure and development; The surface of the substrate coated with the photoresist is ion-etched, and the photoresist remaining on the substrate is removed, so that the first surface of the substrate is concave-convex, and both the concave and convex are trapezoidal.

5. The method for preparing an epitaxial AlGaN / GaN heterojunction device on a Si substrate according to claim 3, characterized in that: Performing ion implantation on the first surface of the substrate includes: The substrate is placed in an ion implantation device, and P ions are implanted on the first surface of the substrate at an implantation concentration of 1×10 11 ~5×10 11 cm -2 , the implantation energy is 28 to 32 keV, and the implantation angle is an incident angle of 6 to 8° with the first surface of the substrate; After the injection is completed, the substrate is placed in an acetone solution and ultrasonically cleaned for 18 to 22 minutes; The cleaned substrate is placed in a drying oven, dried at 65-75°C, and then immersed in a 10-20% dilute hydrochloric acid solution for 55-65s. The immersed substrate is placed in a drying oven and dried at 125-135°C.

6. The method for preparing an epitaxial AlGaN / GaN heterojunction device on a Si substrate according to claim 3, characterized in that: Growing a nucleation layer on the first surface of the substrate includes: A metal organic chemical vapor deposition process is adopted to grow a nucleation layer on the first surface of the substrate, the thickness of the nucleation layer is 170-220 nm, and the material of the nucleation layer is AlN.

7. The method for preparing an epitaxial AlGaN / GaN heterojunction device on a Si substrate according to claim 3, characterized in that: Growing a first superlattice layer on the surface of the nucleation layer comprises: A metal organic chemical vapor deposition process is used to grow 40 to 45 superlattice periodic structures on the surface of the nucleation layer to obtain a first superlattice layer with a thickness of 400 to 480 nm. The material of the first superlattice layer is AlN / Al x Ga 1-x The adjustment range of N and Al content is 0.7 to 0.

75.

8. The method for preparing an epitaxial AlGaN / GaN heterojunction device on a Si substrate according to claim 3, characterized in that: Growing a first buffer layer on the surface of the first superlattice layer comprises: A first buffer layer is grown on the surface of the first superlattice layer by using a metal organic chemical vapor deposition process. The thickness of the first buffer layer is 1000-1200 nm. The material of the first buffer layer is Al x Ga 1-x The adjustment range of N and Al content is 0.3 to 0.

4.

9. The method for preparing an epitaxial AlGaN / GaN heterojunction device on a Si substrate according to claim 3, characterized in that: Growing a second superlattice layer on the surface of the first buffer layer comprises: By adopting a metal organic chemical vapor deposition process, 47 to 50 superlattice periodic structures are grown on the surface of the first buffer layer to obtain a second superlattice layer with a thickness of 1170 to 1280 nm, wherein the material of the second superlattice layer is AlN / GaN.

10. The method for preparing an epitaxial AlGaN / GaN heterojunction device on a Si substrate according to claim 3, characterized in that: Growing a second buffer layer on the surface of the second superlattice layer comprises: A second buffer layer is grown on the surface of the second superlattice layer by using a metal organic chemical vapor deposition process. The thickness of the second buffer layer is 2200-2300 nm, and the material of the second buffer layer is GaN.

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