HEMT device epitaxial structure based on GaN material and application thereof
By employing PSS processing and an AlGaN/GaN composite structure in GaN-based HEMT devices, the epitaxial defect problem caused by lattice mismatch was solved, thereby improving the crystal quality and performance of the devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2026-03-27
AI Technical Summary
In existing technologies, GaN-based HEMT devices suffer from lattice and thermal mismatches between the substrate and in-situ AlN/GaN, resulting in numerous epitaxial defects and leakage channels that affect device performance.
The substrate is treated with PSS to form a nanoscale patterned array to reduce dislocation density, and a high-quality AlN buffer layer is formed on the substrate. Combined with the AlGaN/GaN composite structure and the spaced doped lattice layer, impurities are blocked from penetrating, thus improving crystal quality.
It effectively reduces epitaxial defects, improves crystal quality, reduces leakage current channels, and enhances device performance and withstand voltage.
Smart Images
Figure CN121751673A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor device technology, and in particular to an epitaxial structure of a GaN-based HEMT device and its applications. Background Technology
[0002] Currently, the mainstream methods for growing GaN-based HMET devices on substrates mainly employ in-situ AlN or GaN nucleation layers with a thickness of 20–100 nm. However, during in-situ high-temperature growth, impurities such as O, Si, and C from the substrate or MO source diffuse into the GaN, forming shallow donors and ultimately creating leakage channels that affect device performance. Because of the significant lattice and thermal mismatch between the substrate and the in-situ AlN / GaN, substantial defects exist during MOCVD in-situ growth, leading to the formation of numerous leakage channels extending into the GaN layer.
[0003] Therefore, solving epitaxial defects and improving crystal quality are key to solving the failure problem of GaN-based HMET devices. Summary of the Invention
[0004] This invention provides an epitaxial structure for HEMT devices based on GaN material and its application.
[0005] In a first aspect, embodiments of the present invention provide an epitaxial structure for a GaN-based HEMT device, comprising:
[0006] Substrate;
[0007] A first buffer layer is formed on the substrate;
[0008] Stacks formed on the first buffer layer;
[0009] A channel layer formed on the stack;
[0010] A barrier layer is formed on the channel layer;
[0011] The stack includes a plurality of stacked units stacked sequentially along a direction away from the substrate. Each stacked unit includes an AlGaN sublayer near the first buffer layer, a first GaN-containing lattice layer disposed on the AlGaN sublayer, and a second GaN-containing lattice layer disposed on the first lattice layer. The first lattice layer is a doped lattice layer, and the second lattice layer is an undoped lattice layer.
[0012] Secondly, embodiments of the present invention provide a method for fabricating an epitaxial structure of a HEMT device based on GaN material, comprising:
[0013] Provide substrate;
[0014] A first buffer layer is formed on the substrate;
[0015] A stack is formed on the first buffer layer;
[0016] A channel layer is formed on the stack;
[0017] A barrier layer is formed on the channel layer;
[0018] The stack includes a plurality of stacked units stacked sequentially along a direction away from the substrate. Each stacked unit includes an AlGaN sublayer near the first buffer layer, a first GaN-containing lattice layer disposed on the AlGaN sublayer, and a second GaN-containing lattice layer disposed on the first lattice layer. The first lattice layer is a doped lattice layer, and the second lattice layer is an undoped lattice layer.
[0019] Thirdly, embodiments of the present invention provide a GaN-based HEMT device, the HEMT device comprising:
[0020] Substrate;
[0021] A first buffer layer is formed on the substrate;
[0022] Stacks formed on the first buffer layer;
[0023] A channel layer formed on the stack;
[0024] A barrier layer is formed on the channel layer;
[0025] An electrode layer formed on the barrier layer;
[0026] The stack includes a plurality of stacked units stacked sequentially along a direction away from the substrate. Each stacked unit includes an AlGaN sublayer near the first buffer layer, a first GaN-containing lattice layer disposed on the AlGaN sublayer, and a second GaN-containing lattice layer disposed on the first lattice layer. The first lattice layer is a doped lattice layer, and the second lattice layer is an undoped lattice layer.
[0027] Fourthly, embodiments of the present invention provide a power supply device, comprising:
[0028] HEMT devices based on GaN materials, as described above.
[0029] Fifthly, embodiments of the present invention provide an amplifier, comprising:
[0030] HEMT devices based on GaN materials, as described above. Attached Figure Description
[0031] Figure 1This is a schematic diagram of an epitaxial structure of a GaN-based HEMT device according to an embodiment of the present invention;
[0032] Figure 2 This is a schematic diagram of a patterned sapphire substrate according to an embodiment of the present invention;
[0033] Figure 3 This is another schematic diagram of an epitaxial structure of a GaN-based HEMT device according to an embodiment of the present invention;
[0034] Figure 4 This is a schematic flowchart of a method for fabricating an epitaxial structure of a GaN-based HEMT device according to an embodiment of the present invention;
[0035] Figure 5 This is a schematic diagram of the structure of a GaN-based HEMT device according to an embodiment of the present invention;
[0036] Figure 6 This is a schematic diagram of the structure of a power supply device according to an embodiment of the present invention;
[0037] Figure 7 This is a schematic diagram of the structure of an amplifier according to an embodiment of the present invention;
[0038] in, Figure 1 and Figure 3 In the diagram, 3 represents a stacked layer; 31 represents a stacked unit; AlGaN represents an AlGaN sublayer; GaN1 represents the first lattice layer; and GaN2 represents the second lattice layer.
[0039] Figure 5 In the diagram, 450 represents a HEMT device; 453 represents a stacked layer; 4531 represents a stacked unit; AlGaN represents an AlGaN sublayer; GaN1 represents the first lattice layer; and GaN2 represents the second lattice layer.
[0040] Figure 6 In the following categories: 460. Power supply device; 461. High-voltage primary circuit; 462. Low-voltage secondary circuit; 463. Transformer; 464. AC power supply; 465. Bridge rectifier circuit; 466. Switching device; 467. Single switching device; 468. Switching device.
[0041] Figure 7 In the diagram, 470 is an amplifier; 471 is a digital predistortion circuit; 472 is a mixer; 473 is a power amplifier; and 474 is a directional coupler. Detailed Implementation
[0042] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.
[0043] In the description of this invention, it should be understood that the terms "first" and "second," etc., are used to distinguish different objects, rather than to describe a specific order.
[0044] like Figure 1 As shown, this embodiment of the invention provides an epitaxial structure for a GaN-based HEMT device, comprising:
[0045] Substrate 1;
[0046] A first buffer layer 2 is formed on the substrate 1;
[0047] The stacked layer 3 is formed on the first buffer layer 2;
[0048] The channel layer 4 is formed on the stack 3;
[0049] Barrier layer 5 is formed on channel layer 4.
[0050] Substrate 1; wherein the substrate material is one of sapphire, silicon, and silicon carbide. In this embodiment, the substrate material is sapphire, and a nanoscale patterned array is formed on the surface of the substrate facing the first buffer layer. Specifically, the nanoscale patterned array is patterned using the PSS (Patterned Sapphire Substrate) method to provide subsequent nucleation sites, which can annihilate dislocations, reduce dislocation density, and improve nucleation quality. Further, the patterning process is as follows: bottom width 3µm, height 2µm, pattern spacing 1-2µm, see [reference needed]. Figure 2 .in, Figure 2 The left side is a top view of the PSS, and the right side is a side view of the PSS.
[0051] The following is a detailed introduction to the PSS method: PSS involves growing a dry etching mask on a sapphire substrate, etching the mask using standard photolithography, etching the sapphire using ICP etching technology, removing the mask, and then growing GaN material on it, thus transforming the longitudinal epitaxy of the GaN material into lateral epitaxy.
[0052] A first buffer layer 2 is formed on the substrate 1. The material of the first buffer layer is AlN. To address the mismatch between the nucleation layer and the substrate, forming a high-quality AlN thin film on the substrate facilitates subsequent nucleation, essentially growing a nucleation layer on the AlN thin film and avoiding lattice mismatch. Specifically, the first buffer layer is formed on the substrate using magnetron sputtering or atomic layer deposition.
[0053] In this embodiment, a first buffer layer is formed on the substrate using PVD (Physical Vapor Deposition), specifically magnetron sputtering. In a vacuum-sealed, oxygen-free atmosphere, an argon pretreatment process is employed, with an argon flow rate of 10–200 sccm (standard milliliters / minute) and a sputtering power of 2000–3500 W, ultimately forming a first buffer layer with a thickness of 30–50 nm. The oxygen-free environment allows for precise control of oxygen defect content, enabling the subsequent GaN crystal growth on the first buffer layer to achieve a crystal quality below 500 g / mol.
[0054] A stack 3 is formed on the first buffer layer 2. In order to prevent oxygen and aluminum impurity atoms from penetrating upward into the first buffer layer and the substrate at high temperatures, the present invention forms a stack 3 on the first buffer layer.
[0055] The thickness of the stack is 150–200 nm, which is beneficial for increasing the distance between the substrate and the channel layer. Specifically, the stack 3 includes several stack units 31 stacked sequentially along the direction away from the substrate. Each stack unit includes an AlGaN sublayer (AlGaN) near the first buffer layer, a first lattice layer (GaN1) containing GaN disposed on the AlGaN sublayer, and a second lattice layer (GaN2) containing GaN disposed on the first lattice layer, i.e., an AlGaN / GaN1 / GaN2 three-segment structure. In this embodiment, the stack includes 6–8 stack units. It should be noted that since the AlGaN sublayer has a certain effect of increasing the potential barrier, it can restrict the movement of electrons in the channel layer and improve electron mobility. However, the AlGaN sublayer is unstable and has poor nucleation quality. Therefore, this invention adopts an AlGaN / GaN interleaved growth mode, which can buffer stress and has a certain effect of improving crystal quality.
[0056] The following is a detailed description of the growth mechanism of stacked layers:
[0057] 1) AlGaN sublayer (AlGaN): The material of the AlGaN sublayer is Al x Ga (1-x)N, with a thickness of 3-5 nm, where x is between 0.18 and 0.25, represents the Al composition. It should be noted that when the Al composition is between 0.18 and 0.25, the AlGaN sublayer is a stress-free epitaxial layer; below 0.18, it exhibits tensile stress; above 0.25, it exhibits compressive stress. Therefore, to obtain a high-quality AlGaN sublayer, this embodiment controls x in each stack unit's AlGaN sublayer to approximately 0.2, at which point the AlGaN sublayer is a stress-free epitaxial layer. Specifically, this embodiment uses an MOCVD process, with a deposition temperature of approximately 800°C. The NH3 injection rate gradually changes from 0 sccm to 100 ± 50 sccm over approximately 10 seconds, introducing TMAl and TMGa while controlling the TMAl intake to form an Al sublayer with an Al composition of 0.2. 0.2 Ga 0.8 N thin film, with a thickness of 3-5 nm.
[0058] 2) First Lattice Layer (GaN1): The first lattice layer is a doped lattice layer. Specifically, the first lattice layer is a lattice layer doped with acceptor impurities. Further, the dopant element of the first lattice layer is iron (Fe), and its thickness is 5–10 nm. Fe, as a deep-level acceptor impurity, significantly improves the resistivity and breakdown voltage of GaN materials when introduced into them. However, due to the memory effect of Fe, in order to minimize the Fe doping concentration at the channel layer, the doping concentration in several first lattice layers in the stack is gradually reduced along the direction away from the substrate. In this embodiment, Cp2Fe is introduced into each first lattice layer in a gradually decreasing manner, so that the Fe doping concentration decreases from 10 nm to 10 nm. 18 / cm 3 Reduced to 10 layer by layer 17 / cm 3 In other words, the Fe doping concentration in the first lattice layer is 10. 18 / cm 3 The Fe doping concentration in the last first lattice layer is 10. 17 / cm 3 Specifically, this embodiment employs MOCVD technology, with a deposition temperature of approximately 1000℃, an NH3 flux of 300±50 sccm, and the introduction of TMGa and Cp2Fe while controlling the Cp2Fe uptake to achieve a maximum Fe doping concentration of 10. 18 / cm 3 The minimum doping concentration is 10. 17 / cm 3 The thickness is 5-10 nm.
[0059] 3) Second lattice layer (GaN2): The second lattice layer is an undoped lattice layer with a thickness of 5–10 nm. It should be noted that the deposition temperature for forming the second lattice layer is higher than that for forming the first lattice layer. Specifically, the deposition temperature for forming the second lattice layer is 50–100 °C higher than that for forming the first lattice layer. Furthermore, the second lattice layer is not doped with acceptor impurities; its primary function is to adjust the crystal quality at the interface. High-temperature treatment without acceptor impurities results in a clearer AlGaN / GaN interface, which is more favorable for subsequent growth. It can be understood that AlGaN / GaN causes dislocations in the underlying layer to annihilate at the interface, and the repeated stacked units increase the chance of dislocation annihilation. The high-temperature treatment process is more conducive to the two-dimensional growth of GaN, repairing rough interfaces, blocking dislocations, and reducing dislocation density. Specifically, this embodiment uses MOCVD technology, with a deposition temperature of approximately 1100 °C, an NH3 flux of 300 ± 50 sccm, and TMGa introduced, with a thickness of 5–10 nm.
[0060] In this embodiment, 6 to 8 stacked units are sequentially stacked to form a thickness of 150 to 200 nm. The Fe doping concentration varies between each stacked unit, gradually decreasing the Cp₂Fe injection rate, so that the Fe doping concentration in the first lattice layer of the last stacked unit is reduced to 10. 17 / cm 3 It should be noted that, since the pre-reaction between TMAl and NH3 is relatively strong, in order to avoid generating a strong pre-reaction, the deposition temperature of AlGaN / GaN1 / GaN2 in each stack unit is set to approximately 800 / 1000 / 1100℃, respectively. Furthermore, the NH3 introduction rate gradually changes from approximately 100 sccm to approximately 300 sccm in the AlGaN / GaN stack unit.
[0061] A channel layer 4 is formed on the stack 3. The channel layer is made of GaN, with a deposition temperature of 1100–1200°C and a thickness of 300–500 nm. In this embodiment, TMGa and NH3 are introduced into the channel layer.
[0062] A barrier layer 5 is formed on the channel layer 4. The material of the barrier layer 5 is Al. x Ga (1-x) The N alloy has an Al content of 0.2–0.3% and a deposition temperature of 1100–1200°C. In this embodiment, the barrier layer thickness is 30 nm.
[0063] Furthermore, such as Figure 3 As shown, a second buffer layer is also disposed on the stack 3. Specifically, the material of the second buffer layer is GaN, which is disposed between the stack and the channel layer, the deposition temperature is 1000-1100℃, and the thickness is 500-1000nm. In this embodiment, TMGa and NH3 are introduced into the second buffer layer.
[0064] This invention discloses an epitaxial structure for a GaN-based HEMT device. A high-quality first buffer layer is formed by thin-film deposition, which avoids lattice mismatch between the nucleation layer and the substrate. An AlGaN / GaN composite structure is used to prevent impurity atoms such as oxygen and aluminum from penetrating into the second buffer layer. Furthermore, spaced doping with acceptor impurities significantly improves the resistivity and breakdown voltage of the material.
[0065] like Figure 4 As shown, this embodiment of the invention provides a method for fabricating an epitaxial structure of a GaN-based HEMT device, including the following steps:
[0066] S1, Provide a substrate;
[0067] S2. Form a first buffer layer on the substrate;
[0068] Specifically, a first buffer layer is formed on the substrate using magnetron sputtering or atomic layer deposition. The material of the first buffer layer is AlN.
[0069] S3. Form a stack on the first buffer layer;
[0070] Specifically, the stack includes a plurality of stacked units stacked sequentially along the direction away from the substrate. Each stacked unit includes an AlGaN sublayer near the first buffer layer, a first lattice layer containing GaN disposed on the AlGaN sublayer, and a second lattice layer containing GaN disposed on the first lattice layer. The first lattice layer is a doped lattice layer, and the second lattice layer is an undoped lattice layer.
[0071] Further, step S3 includes at least: providing a first deposition temperature for forming the first lattice layer; and providing a second deposition temperature for forming the second lattice layer. The second deposition temperature is higher than the first deposition temperature.
[0072] S4. Forming channel layers on the stack;
[0073] S5. A barrier layer is formed on the channel layer.
[0074] It should be noted that the specific limitations of the fabrication method of a GaN-based HEMT device epitaxial structure are as described above regarding the limitations of a GaN-based HEMT device epitaxial structure. The two have the same function and role, and will not be repeated here.
[0075] like Figure 5 As shown, this embodiment of the invention provides a GaN-based HEMT device, the HEMT device 450 comprising:
[0076] Substrate 451;
[0077] A first buffer layer 452 is formed on the substrate 451;
[0078] A stack 453 is formed on the first buffer layer 452;
[0079] A channel layer 454 is formed on the stack 453;
[0080] A barrier layer 455 is formed on the channel layer 454;
[0081] An electrode layer 456 is formed on the barrier layer 455;
[0082] The stack 453 includes a plurality of stack units 4531 stacked sequentially along the direction away from the substrate. Each stack unit 4531 includes an AlGaN sublayer (AlGaN) near the first buffer layer, a first lattice layer (GaN1) containing GaN disposed on the AlGaN sublayer, and a second lattice layer (GaN2) containing GaN disposed on the first lattice layer. The first lattice layer is a doped lattice layer, and the second lattice layer is an undoped lattice layer.
[0083] It should be noted that for specific limitations regarding a GaN-based HEMT device, please refer to the limitations on the epitaxial structure of a GaN-based HEMT device mentioned above. The two have the same function and role, and will not be repeated here.
[0084] like Figure 6 As shown, an embodiment of the present invention provides a power supply device that uses a GaN-based HEMT device as described above.
[0085] Specifically, the power supply device 460 includes a high-voltage primary circuit 461, a low-voltage secondary circuit 462, and a transformer 463 disposed between the primary circuit 461 and the secondary circuit 462.
[0086] The primary circuit 461 includes an AC power supply 464, a bridge rectifier circuit 465, multiple switching devices 466, and a single switching device 467. The secondary circuit 462 includes multiple switching devices 468.
[0087] exist Figure 6 In this embodiment, a GaN-based HEMT device is used as switching devices 466 and 467, as described above. Switching devices 466 and 467 in the primary circuit 461 are normally-off semiconductors. A conventional metal-insulator-semiconductor field-effect transistor (MISFET) formed of silicon is used as switching device 468 in the secondary circuit 462.
[0088] like Figure 7As shown, an embodiment of the present invention provides an amplifier that uses a GaN-based HEMT device as described above.
[0089] Specifically, amplifier 470 can be used as a high-power amplifier, for example, for a mobile phone base station. Amplifier 470 includes digital predistortion circuitry 471, mixer 472, power amplifier 473, and directional coupler 474.
[0090] Digital predistortion circuit 471 compensates for nonlinear distortion of the input signal. Mixer 472 mixes the AC signal and the input signal with compensated nonlinear distortion. Power amplifier 473 amplifies the input signal mixed with the AC signal.
[0091] exist Figure 7 In this configuration, power amplifier 473 includes a GaN-based HEMT device as described above. Directional coupler 474 monitors input and output signals, etc. Figure 7 In the circuit, the input signal and the AC signal can be mixed by the mixer 472 and transmitted to the digital predistortion circuit 471 through the switching operation.
[0092] In summary, the present invention provides an epitaxial structure for a GaN-based HEMT device and its application. It employs thin-film deposition to form a high-quality first buffer layer, which avoids lattice mismatch between the nucleation layer and the substrate. The use of an AlGaN / GaN composite structure prevents impurity atoms such as oxygen and aluminum from penetrating into the second buffer layer. Furthermore, spaced doping with acceptor impurities significantly improves the resistivity and breakdown voltage of the material.
[0093] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of the various embodiments, refer to each other. Each embodiment focuses on its differences from other embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as these combinations of technical features do not contradict each other, they should be considered within the scope of this specification.
[0094] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.
Claims
1. An epitaxial structure for a HEMT device based on GaN material, characterized in that, include: Substrate; A first buffer layer is formed on the substrate; Stacks formed on the first buffer layer; A channel layer formed on the stack; A barrier layer is formed on the channel layer; The stack includes a plurality of stacked units stacked sequentially along a direction away from the substrate. Each stacked unit includes an AlGaN sublayer near the first buffer layer, a first GaN-containing lattice layer disposed on the AlGaN sublayer, and a second GaN-containing lattice layer disposed on the first lattice layer. The first lattice layer is a doped lattice layer, and the second lattice layer is an undoped lattice layer.
2. The epitaxial structure of a GaN-based HEMT device according to claim 1, characterized in that, The first buffer layer is made of AlN and is formed on the substrate by magnetron sputtering or atomic layer deposition.
3. The epitaxial structure of a GaN-based HEMT device according to claim 1, characterized in that, The first lattice layer is a lattice layer doped with acceptor impurities.
4. The epitaxial structure of a GaN-based HEMT device according to claim 3, characterized in that, The doping element in the first lattice layer is iron.
5. The epitaxial structure of a GaN-based HEMT device according to claim 1 or 4, characterized in that, Along the direction away from the substrate, the doping concentration in several of the first lattice layers in the stack decreases layer by layer.
6. The epitaxial structure of a GaN-based HEMT device according to claim 5, characterized in that, The doping concentration in several of the first lattice layers in the stack is from 10 18 / cm 3 Reduced to 10 layer by layer 17 / cm 3 .
7. The epitaxial structure of a GaN-based HEMT device according to claim 1, characterized in that, The thickness of the stack is 150–200 nm, and it includes 6–8 stack units.
8. The epitaxial structure of a GaN-based HEMT device according to claim 1, characterized in that, The thickness of both the first lattice layer and the second lattice layer is 5–10 nm.
9. The epitaxial structure of a GaN-based HEMT device according to claim 1, characterized in that, The deposition temperature used to form the second lattice layer is higher than the deposition temperature used to form the first lattice layer.
10. The epitaxial structure of a GaN-based HEMT device according to claim 9, characterized in that, The deposition temperature used to form the second lattice layer is 50 to 100°C higher than the deposition temperature used to form the first lattice layer.
11. The epitaxial structure of a GaN-based HEMT device according to claim 1, characterized in that, The material of the AlGaN sublayer is Al x Ga (1-x) N, with a thickness of 3–5 nm, where x is between 0.18 and 0.
25.
12. The epitaxial structure of a GaN-based HEMT device according to claim 1, characterized in that, The substrate is made of sapphire, and a nanoscale pattern array is formed on the surface of the substrate facing the first buffer layer.
13. The epitaxial structure of a GaN-based HEMT device according to claim 1, characterized in that, A second buffer layer is also provided on the stack, and the material of the second buffer layer is GaN.
14. A method for fabricating an epitaxial structure of a GaN-based HEMT device, characterized in that, include: Provide substrate; A first buffer layer is formed on the substrate; A stack is formed on the first buffer layer; A channel layer is formed on the stack; A barrier layer is formed on the channel layer; The stack includes a plurality of stacked units stacked sequentially along a direction away from the substrate. Each stacked unit includes an AlGaN sublayer near the first buffer layer, a first GaN-containing lattice layer disposed on the AlGaN sublayer, and a second GaN-containing lattice layer disposed on the first lattice layer. The first lattice layer is a doped lattice layer, and the second lattice layer is an undoped lattice layer.
15. The preparation method according to claim 14, characterized in that, The formation of the first buffer layer on the substrate includes: A first buffer layer is formed on the substrate using magnetron sputtering or atomic layer deposition; wherein the material of the first buffer layer is AlN.
16. The preparation method according to claim 14, characterized in that, The process of forming a stack on the first buffer layer includes at least: A first deposition temperature is provided for forming the first lattice layer; A second deposition temperature is provided for forming the second lattice layer; The second deposition temperature is higher than the first deposition temperature.
17. A HEMT device based on GaN material, characterized in that, The HEMT device includes: Substrate; A first buffer layer is formed on the substrate; Stacks formed on the first buffer layer; A channel layer formed on the stack; A barrier layer is formed on the channel layer; An electrode layer formed on the barrier layer; The stack includes a plurality of stacked units stacked sequentially along a direction away from the substrate. Each stacked unit includes an AlGaN sublayer near the first buffer layer, a first GaN-containing lattice layer disposed on the AlGaN sublayer, and a second GaN-containing lattice layer disposed on the first lattice layer. The first lattice layer is a doped lattice layer, and the second lattice layer is an undoped lattice layer.
18. A power supply device, characterized in that, include: The HEMT device based on GaN material according to claim 17.
19. An amplifier, characterized in that, include: The HEMT device based on GaN material according to claim 17.