HEMT epitaxial structure
By introducing an alternating structure of a current-dispersing layer and a second high-resistivity layer into the HEMT epitaxial structure, the voltage surge problem caused by sudden waves is solved, and the durability and stability of the HEMT epitaxial structure are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-06
- Publication Date
- 2026-04-03
AI Technical Summary
Existing HEMT epitaxial structures cannot effectively block surges during power outages, leading to leakage or burnout. Furthermore, thickening the C-GaN layer for protection can cause warping and surface roughness issues.
A composite barrier layer is adopted, including an alternating structure of a current dispersion layer and a second high-resistivity layer. Through current dispersion and rebound mechanisms, the voltage impact of surge current on the HEMT epitaxial structure is reduced.
It effectively reduces the impact of surge current on HEMT epitaxial structures, improves their service life, and avoids warping and surface roughness problems.
Smart Images
Figure CN224083954U_ABST
Abstract
Description
Technical Field
[0001] This technology relates to the field of HEMT, and in particular to HEMT epitaxial structures. Background Technology
[0002] Existing HEMT (High Electron Mobility Transistor) epitaxial structures are prone to leakage or even burnout due to their inability to effectively block the surge generated at the moment of power failure. A common method is to thicken the C-GaN layer (carbide doped with carbon, used to create the high-resistivity layer in the HEMT epitaxial structure). Although thickening the C-GaN layer can prevent the above problems, to effectively prevent them, the thickness of the C-GaN layer often needs to be significantly increased, which can easily cause warping of the HEMT epitaxial structure. Furthermore, using carbon-doped GaN can easily result in a rough surface and contamination of the HEMT epitaxial structure. Utility Model Content
[0003] This application aims to provide a HEMT epitaxial structure that can solve the technical problem in the background art that the existing HEMT epitaxial structure cannot effectively block the surge generated at the moment of power failure.
[0004] To achieve the above objectives, this application provides a HEMT epitaxial structure, comprising a substrate, a polymer layer, a first high-resistivity layer, a composite barrier layer, an intermediate layer, and a channel layer sequentially stacked along a first direction. The composite barrier layer includes at least one barrier group, and the barrier group includes a current-dispersing layer and a second high-resistivity layer stacked along the first direction on the current-dispersing layer.
[0005] Compared with existing technologies, the blocking group of this application includes a current dispersing layer and a second high-resistivity layer stacked on the current dispersing layer along a first direction. When a surge current enters the composite blocking layer, the current dispersing layer disperses the input current and outputs it when the blocking group is impacted by the surge current, while the second high-resistivity layer partially bounces the input current, allowing only a portion of the current to enter the next layer. Through the current dispersing effect of the current dispersing layer and the current bounce effect of the second high-resistivity layer, the voltage surge per unit area of the HEMT epitaxial structure can be reduced, the impact of surge current on the HEMT epitaxial structure can be reduced, and the service life of the HEMT epitaxial structure can be improved.
[0006] Optionally, the material of the current dispersing layer includes at least one of GaN, InGaN, and silicon-doped GaN.
[0007] Optionally, the thickness of the current-dispersing layer in the first direction is 50-500 nm.
[0008] Optionally, the material of the second high-resistivity layer includes at least one of carbon-doped GaN and iron-doped GaN.
[0009] Optionally, the doping concentration of the second high-resistivity layer in GaN doped with iron or carbon is 1*10⁻⁶. 18 -5*10 19 amu / cm 3 .
[0010] Optionally, the thickness of the second high-resistivity layer in the first direction is 100-1000 nm.
[0011] Optionally, the sheet resistance of the current dispersing layer is 10-1000 Ω·mm, and the sheet resistance of the second high-resistivity layer is 10,000 to 1,000,000 Ω·mm.
[0012] Optionally, the number of the blocking groups is less than or equal to 10.
[0013] Optionally, the number of the blocking groups is greater than or equal to 2, and each of the current dispersing layers and each of the second high-resistivity layers are alternately stacked.
[0014] Optionally, the thickness of the composite barrier layer in the first direction is less than or equal to 10 μm. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the existing HEMT epitaxial structure.
[0016] Figure 2 This is a schematic diagram of the HEMT epitaxial structure according to an embodiment of this application.
[0017] Figure 3 This is a schematic diagram illustrating the principle of dispersion and rebound surge current in the HEMT epitaxial structure according to an embodiment of this application. Detailed Implementation
[0018] To explain in detail the technical content, structural features, objectives and effects of this application, the following description is provided in conjunction with the embodiments and accompanying drawings.
[0019] Surges can easily form electric field spikes in the HEMT epitaxial structure. This local electric field concentration can cause premature breakdown of the HEMT epitaxial structure before reaching the theoretical breakdown electric field strength, resulting in leakage current in the HEMT epitaxial structure or even device burnout.
[0020] Please see Figure 1Therefore, an existing HEMT epitaxial structure includes a substrate A1 (made of AlGaN), a polymer layer A2 (made of IGaN), a first high-resistivity layer A3 (made of C-GaN), an intermediate layer A4 (made of UGaN), and a channel layer A5 (made of Sapphire) stacked sequentially along a first direction. To reduce surge damage to the HEMT, the thickness of the first high-resistivity layer A3 in the first direction needs to be significantly increased; however, this inevitably leads to warping in the HEMT epitaxial structure.
[0021] This application disperses the surge to various points on the surface of the HEMT epitaxial structure that is subjected to the surge, thereby reducing the voltage surge per unit area.
[0022] For this, please refer to Figure 2 and Figure 3 This application discloses a HEMT epitaxial structure, including a substrate 1, a polymer layer 2, a first high-resistivity layer 3, a composite barrier layer 4, an intermediate layer 5 and a channel layer 6 stacked sequentially in a first direction. The composite barrier layer 4 includes at least one barrier group 41, and the barrier group 41 includes a current dispersing layer 411 and a second high-resistivity layer 412 stacked on the current dispersing layer 411 along the first direction.
[0023] The following is combined with Figure 3 The principle and beneficial effects of the composite blocking layer 4 of this application are briefly described, taking three blocking groups 41 as an example; the same applies to other cases and will not be elaborated further. When a surge current enters the second high-resistivity layer 412A, the second high-resistivity layer 412A will reflect a portion of the surge current (black arrow in the figure), while the other portion enters the second high-resistivity layer 412A. When the current in the second high-resistivity layer 412A enters the current dispersion layer 411A, the current will be divided into multiple current streams by the current dispersion layer 411A. When the current in the current dispersion layer 411A enters the second high-resistivity layer 412B, a portion of the current will be reflected by the second high-resistivity layer 412B, while the other portion will enter the second high-resistivity layer 412B. When the current in layer 12B enters the current dispersion layer 411B, it further disperses the current in the second high-resistivity layer 412B. When the current in the current dispersion layer 411B enters the second high-resistivity layer 412C, part of the current is bounced off the second high-resistivity layer 412C, and another part enters the second high-resistivity layer 412C... and so on. After the current is dispersed by each current dispersion layer 411 and partially bounced off by each second high-resistivity layer 412, the voltage per unit area of the HEMT epitaxial structure is significantly reduced when the current is finally output from the composite barrier layer 4. Therefore, the composite barrier layer 4 of this application can effectively prevent surge currents from damaging the HEMT epitaxial structure.
[0024] In some embodiments, the substrate 1 is made of AlGaN, the polymer layer 2 is made of IGaN, the first high-resistivity layer 3 is made of C-GaN, the intermediate layer 5 is made of UGaN, and the channel layer 6 is made of Sapphire. Of course, this is not the only possibility.
[0025] If the thickness of the composite barrier layer 4 along the first direction is too large, it can easily cause epitaxial peeling of the HEMT epitaxial structure. Therefore, it is necessary to select a suitable material and minimize the thickness of the composite barrier layer 4 in the first direction.
[0026] In some embodiments, the material of the current dispersing layer 411 includes at least one of GaN, InGaN, and silicon-doped GaN.
[0027] Optionally, the thickness of the current dispersing layer 411 in the first direction is 50-500 nm.
[0028] In some embodiments, the material of the second high-resistivity layer 412 includes at least one of carbon-doped GaN and iron-doped GaN.
[0029] Optionally, the thickness of the second high-resistivity layer 412 in the first direction is 100-1000 nm.
[0030] Optionally, the doping concentration of the carbon-doped or iron-doped GaN in the second high-resistivity layer 412 is 1*10⁻⁶. 18 -5*10 19 amu / cm 3 Wherein, amu is the atomic mass unit, 1 gram = 6.02 × 10⁻⁶. 23 amu.
[0031] In some embodiments, the sheet resistance of the current dispersing layer 411 is 10-1000 Ω·mm, and the sheet resistance of the second high-resistivity layer 412 is 10,000 to 1,000,000 Ω·mm.
[0032] In some embodiments, the number of blocking groups 41 is less than or equal to 10.
[0033] Optionally, the number of blocking groups 41 is greater than or equal to 2, and each current dispersing layer 411 and each second high-resistivity layer 412 are alternately stacked. Among them, when the number of blocking groups 41 is 2-3, the HEMT epitaxial structure can withstand a surge of approximately 1700V.
[0034] In some embodiments, the thickness of the composite barrier layer 4 in the first direction is less than or equal to 10 μm.
[0035] The above-disclosed examples are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall fall within the scope of this application.
Claims
1. A HEMT epitaxial structure, characterized in that, The HEMT epitaxial structure comprises, in sequence along a first direction, a substrate, a polymer layer, a first high-resistance layer, a composite barrier layer, an intermediate layer, and a channel layer, wherein the composite barrier layer comprises at least one barrier group, and each barrier group comprises a current dispersion layer and a second high-resistance layer stacked on the current dispersion layer along the first direction.
2. The HEMT epitaxial structure of claim 1, wherein, a thickness of the current dispersion layer along the first direction is 50-500 nm.
3. The HEMT epitaxial structure of claim 1, wherein, a thickness of the second high-resistance layer along the first direction is 100-1000 nm.
4. The HEMT epitaxial structure of claim 1, wherein, a surface resistance of the current dispersion layer is 10-1000 Ω·mm, and a surface resistance of the second high-resistance layer is 10,000-1,000,000 Ω·mm.
5. The HEMT epitaxial structure of claim 1, wherein, a number of the barrier groups is less than or equal to 10.
6. The HEMT epitaxial structure of claim 5, wherein, a number of the barrier groups is greater than or equal to 2, and each current dispersion layer and each second high-resistance layer are alternately stacked.
7. The HEMT epitaxial structure of claim 1, wherein, a thickness of the composite barrier layer along the first direction is less than or equal to 10 um.