Barrier layer structure with asymmetric insertion layer and power device
By employing an asymmetric insertion layer structure in GaN HEMT devices, the electric field distribution is optimized, solving the problem of increased electric field peak caused by lattice differences, improving the breakdown voltage and withstand voltage performance of the devices, and suppressing the current collapse effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Filing Date
- 2026-06-15
- Publication Date
- 2026-07-14
AI Technical Summary
Traditional GaN HEMT devices suffer from excessive polarization charge due to lattice differences in the AlN insertion layer under high voltage conditions. This leads to an increase in local peak electric field, causing tip discharge and performance degradation, which affects the device's withstand voltage rating and reliability.
An asymmetric insertion layer structure is adopted, in which the insertion layer forms first and second insertion segments with different thicknesses between the source and the gate and between the gate and the drain. Combined with the transition segment, a polarization modulation composite barrier structure is formed to optimize the electric field distribution.
It improves the breakdown voltage by 40%~70%, reduces the peak electric field by 30%~60%, suppresses the current collapse effect, improves device performance, and meets the design requirements of high-voltage GaN HEMT.
Smart Images
Figure CN122395986A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor chip technology, and more specifically to a barrier layer structure and power device with an asymmetric insertion layer. Background Technology
[0002] Gallium nitride high electron mobility transistor (GaN HEMT) is a field-effect transistor based on gallium nitride, a third-generation wide-bandgap semiconductor material. It is a core device in high-frequency and high-power applications and is widely used in radio frequency communication and power electronics industries.
[0003] In traditional GaN HEMT designs, to increase the mobility and concentration of the two-dimensional electron gas and improve device performance, AlN with a higher bandgap is generally used as an insertion layer to prevent electron leakage to the barrier layer, such as... Figure 1 As shown, the huge lattice difference between AlN and GaN results in extremely strong polarization charges. Under high voltage conditions, the crystal interface of the material needs to withstand extremely high vertical electric field stress. Especially in the gate edge region, the uniform AlN insertion layer cannot provide electric field mitigation and dispersion, which will aggravate the local peak electric field, causing tip discharge and thus reducing the device's withstand voltage rating. This effect will cause cumulative damage to the device during use, leading to device performance degradation and eventually breakdown at lower voltages. Summary of the Invention
[0004] One object of the present invention is to provide a barrier layer structure with an asymmetric insertion layer.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A barrier layer structure with an asymmetric insertion layer includes a barrier layer on which a source, a gate, and a drain are formed. An insertion layer is embedded inside the barrier layer. The insertion layer forms a first insertion segment between the source and the gate and a second insertion segment between the gate and the drain. The thickness of the first insertion segment is a, and the thickness of the second insertion segment is b, where a < b.
[0006] Preferably, in the above technical solution, the thickness of at least one of the first insertion segment and the second insertion segment gradually increases in the direction from the source to the drain.
[0007] Preferably, in the above technical solution, the bottom surfaces of the first insertion segment and the second insertion segment are horizontal and coplanar, and at least one of the top surfaces of the first insertion segment and the second insertion segment extends obliquely upward in the source-to-drain direction.
[0008] Preferably, in the above technical solution, the top surfaces of the first insertion segment and the second insertion segment are horizontal and coplanar, and at least one of the bottom surfaces of the first insertion segment and the second insertion segment extends downward at an angle in the direction from the source to the drain.
[0009] Preferably, in the above technical solution, the thickness of the first insertion segment and the second insertion segment are the same.
[0010] Preferably, the first insertion segment and the second insertion segment have a transition segment, the top surface of the transition segment is connected to the top surface of the first insertion segment and the second insertion segment, the bottom surface of the transition segment is connected to the bottom surface of the first insertion segment and the second insertion segment, and the top and bottom surfaces of the transition segment are horizontal.
[0011] Preferably, the first insertion segment and the second insertion segment have a transition segment, the top surface of the transition segment is connected to the top surfaces of the first insertion segment and the second insertion segment, the bottom surface of the transition segment is connected to the bottom surfaces of the first insertion segment and the second insertion segment, the top surface of the transition segment extends obliquely upward from the first insertion segment to the second insertion segment and / or the bottom surface of the transition segment extends obliquely downward from the first insertion segment to the second insertion segment.
[0012] More preferably, the bottom surfaces of the transition section, the first insertion section, and the second insertion section are horizontal and coplanar, and the top surface of the transition section extends obliquely upward from the first insertion section to the second insertion section.
[0013] More preferably, the bottom surface of the transition section extends downward at an angle from the first insertion section to the second insertion section, and the top surface of the transition section extends upward at an angle from the first insertion section to the second insertion section.
[0014] More preferably, the bottom surfaces of the transition section and the first insertion section are horizontal and coplanar, the top surfaces of the transition section and the second insertion section are horizontal and coplanar, the bottom surface of the first insertion section is lower than the bottom surface of the second insertion section, and the top surface of the first insertion section is lower than the top surface of the second insertion section.
[0015] Preferably, in the above technical solution, the insertion layer is an AlN insertion layer.
[0016] Preferably, in the above technical solution, the insertion layer is a composite insertion layer of AlN and AlGaN.
[0017] More preferably, when the barrier layer is an AlGaN barrier layer, the Al content in the AlN / AlGaN composite insertion layer is higher than the Al content in the AlGaN barrier layer.
[0018] More preferably, the Al content in the AlN / AlGaN composite insertion layer is 0.35~0.5%.
[0019] More preferably, the AlN and AlGaN composite insertion layer includes an AlN sub-insertion layer and an AlGaN sub-insertion layer, which are disposed one above the other.
[0020] Preferably, in the above technical solution, the thickness a of the first insertion segment is 0.5~2 nm; and the thickness b of the second insertion segment is 1.5~5 nm.
[0021] More preferably, the thickness a of the first insertion segment is 0.5~1.5nm; and the thickness b of the second insertion segment is 1.5~5nm.
[0022] Preferably, in the above technical solution, the barrier layer is an AlGaN barrier layer, and satisfies the following: The Al composition in the AlGaN barrier layer is 0.2~0.3; The thickness of the AlGaN barrier layer is 15~30nm.
[0023] Preferably, in the above technical solution, the insertion layer is located in the lower middle part of the barrier layer.
[0024] In a preferred embodiment of the above technical solution, the distance between the bottom surface of the insertion layer and the bottom surface of the barrier layer is 3~8nm.
[0025] Another object of the present invention is to provide a power device with a barrier layer structure having an asymmetric insertion layer.
[0026] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A power device, wherein the power device is a gate field plate, or a source field plate, or a p-GaN gate, or a compressive strain passivation layer, comprising a barrier layer structure having an asymmetric insertion layer.
[0027] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: This invention forms a polarization-modulated composite barrier structure by embedding an asymmetric insertion layer inside the original barrier layer. The spontaneous polarization and piezoelectric polarization effects of the asymmetric insertion layer are much stronger than those of the barrier layer. The thicker insertion layers on the gate and drain sides lead to a higher local barrier. The peak electric field spontaneously migrates from the gate edge to the drain side and gradually decreases, thereby optimizing the distribution of the peak electric field and improving the overall performance of the device. The breakdown voltage of this invention can be increased by 40% to 70%, the peak electric field can be reduced by 30% to 60%, Ron (on-resistance) is basically not degraded, and the current collapse effect is significantly suppressed, which meets the design requirements of high voltage GaN HEMT. Attached Figure Description
[0028] Appendix Figure 1This is a schematic diagram of the barrier layer and insertion layer in the prior art; Appendix Figure 2 This is a schematic diagram of the barrier layer structure with an asymmetric insertion layer in Example 1; Appendix Figure 3 This is a schematic diagram of the barrier layer structure with an asymmetric insertion layer in Example 2; Appendix Figure 4 This is a schematic diagram of the barrier layer structure with an asymmetric insertion layer in Example 3; Appendix Figure 5 This is a schematic diagram of the barrier layer structure with an asymmetric insertion layer in Example 4; Appendix Figure 6 This is a schematic diagram of the barrier layer structure with an asymmetric insertion layer in Example 5; Appendix Figure 7 This is a schematic diagram of the barrier layer structure with an asymmetric insertion layer in Example 6; Appendix Figure 8 This is a schematic diagram of the barrier layer structure with an asymmetric insertion layer in Example 7; Appendix Figure 9 This is a schematic diagram of the power device in Example 7.
[0029] In the attached diagrams above: 1. Barrier layer; 2. Insertion layer; 2a. AlN sub-insertion layer; 2b. AlGaN sub-insertion layer; 20. First insertion segment; 21. Second insertion segment; 22. Transition segment; 3. Channel layer; 4. Passivation layer; S, source; G, gate; D, drain. Detailed Implementation
[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0032] like Figures 1-8 As shown: A barrier layer structure with an asymmetric insertion layer includes a barrier layer 1, on which a source, gate, and drain are formed. Of course, the source, gate, and drain are not necessarily formed directly on the barrier layer 1. In this embodiment: the bottom and top surfaces of the barrier layer 1 are both horizontal.
[0033] Barrier layer 1 is an AlGaN barrier layer, and satisfies the following conditions: the Al composition in the AlGaN barrier layer is 0.2~0.3, and the overall thickness of the AlGaN barrier layer is 15~30nm.
[0034] An insertion layer 2 is embedded inside the barrier layer 1. The insertion layer 2 is located in the lower middle part of the barrier layer 1, and the top and bottom of the insertion layer 2 are completely covered by the barrier layer 1, thus forming a polarization modulation composite barrier structure with the barrier layer 1. Specifically, the bottom surface of the insertion layer 2 is 3~8nm away from the bottom surface of the barrier layer 1, that is, it maintains a distance from the channel layer below the barrier layer 1 and does not directly contact the channel layer and the device surface. The top and bottom of the insertion layer 2 are completely covered by the barrier layer 1.
[0035] The insertion layer 2 forms a first insertion segment 20 between the source and the gate, and a second insertion segment 21 between the gate and the drain. The thickness of the first insertion segment 20 is a, and the thickness of the second insertion segment 21 is b, where a < b. Specifically, the thickness a of the first insertion segment 20 is 0.5~2 nm, preferably 0.5~1.5 nm; the thickness b of the second insertion segment 21 is 1.5~5 nm, preferably 1.5~5 nm. Thus, an asymmetric insertion layer 2 is formed between the source and the gate and between the gate and the drain, realizing the synergistic control of the channel two-dimensional electron gas (2DEG) confinement enhancement and the transverse electric field.
[0036] In one embodiment of this example: the thickness of at least one of the first insertion segment 20 and the second insertion segment 21 gradually increases in the direction from the source to the drain. For example, the thickness of the first insertion segment 20 gradually increases in the direction from the source to the gate, while the thickness of the second insertion segment 21 remains the same; or the thickness of the first insertion segment 20 remains the same, while the thickness of the second insertion segment 21 gradually increases in the direction from the gate to the drain; or the thickness of both the first insertion segment 20 and the second insertion segment 21 gradually increases in the direction from the source to the drain, thereby forming a barrier layer structure of an asymmetric insertion layer with gradually varying thickness.
[0037] In another embodiment of this example: the thickness of the first insertion segment 20 and the second insertion segment 21 are consistent. For example, the first insertion segment 20 and the second insertion segment 21 are directly connected, or there is a transition segment 22 between the first insertion segment 20 and the second insertion segment 21, and the first insertion segment 20 and the second insertion segment 21 are connected through the transition segment 22. However, usually at this time, the top and bottom surfaces of the first insertion segment 20 and the second insertion segment 21 are horizontal.
[0038] For the structure using transition segment 22: the top and bottom surfaces of transition segment 22 can both be horizontal; or the top surface of transition segment 22 can extend upward at an angle from the first insertion segment 20 to the second insertion segment 21 and / or the bottom surface of transition segment 22 can extend downward at an angle from the first insertion segment 20 to the second insertion segment 21. That is, the top and bottom surfaces of transition segment 22 are connected to the first insertion segment 20 and the second insertion segment 21 in a horizontal or inclined manner, thereby forming a barrier layer structure of asymmetric insertion layer with gradually varying thickness.
[0039] The thickness of the insertion layer 2 can be increased by extending its top surface upwards at an angle in the source-to-drain direction and / or extending its bottom surface downwards at an angle in the source-to-drain direction. Its top surface includes the top surfaces of the first insertion segment 20, the second insertion segment 21, and the transition segment 22, and its bottom surface includes the bottom surfaces of the first insertion segment 20, the second insertion segment 21, and the transition segment 22.
[0040] The insertion layer 2 can be a single AlN insertion layer or a composite insertion layer of AlN and AlGaN. That is, the insertion layer 2 can be made of AlN or AlN and AlGaN.
[0041] Regarding the structure of the AlN and AlGaN composite insertion layer, the AlN and AlGaN composite insertion layer specifically includes an AlN sub-insertion layer 2a and an AlGaN sub-insertion layer 2b. That is, the AlN and AlGaN composite insertion layer is composed of an AlN sub-insertion layer 2a and an AlGaN sub-insertion layer 2b. Preferably, the AlN sub-insertion layer 2a and the AlGaN sub-insertion layer 2b are arranged vertically, with the AlN sub-insertion layer 2a located above the AlGaN sub-insertion layer 2b.
[0042] Regarding the composition of the AlN / AlGaN composite insertion layer, since barrier layer 1 is an AlGaN barrier layer, the Al content in the AlN / AlGaN composite insertion layer is higher than that in the AlGaN barrier layer. If the Al content in the AlN / AlGaN composite insertion layer and the AlGaN barrier layer are the same, or if the Al content in the AlN / AlGaN composite insertion layer is lower than that in the AlGaN barrier layer, there will be no peak voltage migration effect, which will weaken the piezoelectric effect. In this embodiment, the Al content in the AlGaN barrier layer is 0.2~0.3, therefore, the Al content in the AlN / AlGaN composite insertion layer is preferably 0.35~0.5. The AlN / AlGaN composite insertion layer can reduce mismatch impact for the gradually changing super-interface structure and improve device stability.
[0043] Example 1: like Figure 2 As shown: In this embodiment, the insertion layer 2 is an AlN insertion layer, which includes a first insertion segment 20 and a second insertion segment 21. The bottom surfaces of the first insertion segment 20 and the second insertion segment 21 are horizontal and coplanar. The top surfaces of the first insertion segment 20 and the second insertion segment 21 extend upward at an angle from the source to the drain. That is, the insertion layer 2 is an asymmetric structure in which the thickness of the first insertion segment 20 and the second insertion segment 21 gradually increases from the source to the drain.
[0044] Example 2: like Figure 3 As shown: In this embodiment, the insertion layer 2 is an AlN insertion layer, which includes a first insertion segment 20 and a second insertion segment 21. The bottom surfaces of the first insertion segment 20 and the second insertion segment 21 are horizontal and coplanar. The thickness of the first insertion segment 20 is consistent, and the bottom surface of the first insertion segment 20 is also horizontal. The top surface of the second insertion segment 21 extends upward at an angle from the gate to the drain. That is, the insertion layer 2 is an asymmetric structure in which the thickness of the first insertion segment 20 remains unchanged, and the thickness of the second insertion segment 21 gradually increases from the gate to the drain.
[0045] Example 3: like Figure 4 As shown: In this embodiment, the insertion layer 2 is an AlN insertion layer, which includes a first insertion segment 20 and a second insertion segment 21. The bottom surfaces of the first insertion segment 20 and the second insertion segment 21 are horizontal and coplanar, and the top surfaces of the first insertion segment 20 and the second insertion segment 21 are both horizontal, so that the thickness of the first insertion segment 20 and the thickness of the second insertion segment 21 are consistent. At the same time, the first insertion segment 20 and the second insertion segment 21 are directly connected, so a step is formed between the top surfaces of the first insertion segment 20 and the second insertion segment 21. That is, the insertion layer 2 is an asymmetric structure with a sudden change in thickness between the first insertion segment 20 and the second insertion segment 21.
[0046] Example 4: like Figure 5 As shown: In this embodiment, the insertion layer 2 is an AlN insertion layer, which includes a first insertion segment 20, a second insertion segment 21, and a transition segment 22. The first insertion segment 20 and the second insertion segment 21 are connected through the transition segment 22. The bottom surfaces of the first insertion segment 20, the second insertion segment 21, and the transition segment 22 are horizontal and coplanar. The top surfaces of the first insertion segment 20 and the second insertion segment 21 are both horizontal, so that the thickness of the first insertion segment 20 and the thickness of the second insertion segment 21 are consistent. The top surface of the transition segment 22 extends obliquely upward from the first insertion segment 20 to the second insertion segment 21. That is, the insertion layer 2 is an asymmetric structure with a gradually changing thickness through the transition segment 22.
[0047] Example 5: like Figure 6 As shown: In this embodiment, the insertion layer 2 is an AlN insertion layer, which includes a first insertion segment 20, a second insertion segment 21, and a transition segment 22. The first insertion segment 20 and the second insertion segment 21 are connected through the transition segment 22. The bottom and top surfaces of the first insertion segment 20 and the second insertion segment 21 are both horizontal, so that the thickness of the first insertion segment 20 and the thickness of the second insertion segment 21 are consistent. The bottom surface of the transition segment 22 extends downward at an angle from the first insertion segment 20 to the second insertion segment 21, and the top surface of the transition segment 22 extends upward at an angle from the first insertion segment 20 to the second insertion segment 21. That is, the insertion layer 2 is an asymmetric structure with a gradually changing thickness through the transition segment 22.
[0048] Example 6: like Figure 7 As shown: In this embodiment, the insertion layer 2 is an AlN insertion layer, which includes a first insertion segment 20, a second insertion segment 21, and a transition segment 22. The first insertion segment 20 and the second insertion segment 21 are connected through the transition segment 22. The bottom and top surfaces of the first insertion segment 20 and the second insertion segment 21 are both horizontal, so that the thickness of the first insertion segment 20 and the second insertion segment 21 are consistent. The bottom surfaces of the transition segment 22 and the first insertion segment 20 are horizontal and coplanar, and the top surfaces of the transition segment 22 and the second insertion segment 21 are horizontal and coplanar. The bottom surface of the first insertion segment 20 is lower than the bottom surface of the second insertion segment 21, and the top surface of the first insertion segment 20 is lower than the top surface of the second insertion segment 21. That is, the insertion layer 2 is an asymmetric structure with a sudden change in thickness through the transition segment 22.
[0049] Example 7: like Figure 8 As shown: This embodiment is basically the same as embodiment four, except that: the insertion layer 2 in this embodiment is a composite insertion layer of AlN and AlGaN, the AlN sub-insertion layer 2a is the same as in embodiment four, and an AlGaN sub-insertion layer 2b is formed below the AlN sub-insertion layer 2a.
[0050] In the above embodiments: Embodiments 1, 2, 4, and 5 adopt a linear smooth gradient structure with no interface steps or lattice abrupt changes, and the interface is clean with no obvious mismatch dislocations or V-shaped defects; the AlN and AlGaN composite insertion layer in Embodiment 7 can further reduce interface strain, improve epitaxial quality, and enhance device reliability compared to a single AlN insertion layer; although Embodiments 3 and 6 are abrupt structures with stepped structures, they have relatively simple manufacturing processes and lower costs.
[0051] Example 8: like Figure 9 As shown: A power device includes a p-GaN gate structure, wherein the p-GaN gate structure has a barrier layer structure with an asymmetric insertion layer. Figure 9 The p-GaN gate structure includes a channel layer 3 from bottom to top, a barrier layer structure with an asymmetric insertion layer, and the barrier layer structure is the barrier layer structure with a composite insertion layer of AlN and AlGaN in Example 7. A P-GaN layer is inserted in the gate region, and the topmost part is a passivation layer 4 and a metal electrode, thereby forming a p-GaN gate enhancement (normally off) HEMT structure.
[0052] Of course, the barrier layer structure of the asymmetric insertion layer in this embodiment can be applied not only to power devices with p-GaN gate structure, but also to power devices such as gate field plates, source field plates, and compressive strain passivation layers, to further improve the voltage withstand uniformity.
[0053] Table 1 shows a comparison of the effects of existing designs, standalone AlN insertion layers, and composite AlN / AlGaN insertion layers in this embodiment: As shown in Table 1, the asymmetric insertion layer in this embodiment forms a high barrier electric field clamping region in the gate region and a gradually changing electric field expansion region in the gate-drain high voltage terminal region, which can reduce the peak electric field of the device in the off state by more than 30%, increase the breakdown voltage by ≥40%, and significantly suppress the current collapse effect.
[0054] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A barrier layer structure with an asymmetric insertion layer, comprising a barrier layer on which a source, a gate, and a drain are formed, characterized in that: An insertion layer is embedded inside the barrier layer. The insertion layer forms a first insertion segment between the source and the gate, and a second insertion segment between the gate and the drain. The thickness of the first insertion segment is a, and the thickness of the second insertion segment is b, where a < b.
2. The barrier layer structure with an asymmetric insertion layer according to claim 1, characterized in that: The thickness of at least one of the first insertion segment and the second insertion segment gradually increases in the direction from the source to the drain.
3. The barrier layer structure with an asymmetric insertion layer according to claim 1 or 2, characterized in that: The bottom surfaces of the first insertion segment and the second insertion segment are horizontal and coplanar, and at least one of the top surfaces of the first insertion segment and the second insertion segment extends obliquely upward in the source-to-drain direction; or The top surfaces of the first and second insertion segments are horizontal, and at least one of the bottom surfaces of the first and second insertion segments extends downward at an angle from the source to the drain.
4. The barrier layer structure with an asymmetric insertion layer according to claim 1, characterized in that: The thickness of the first insertion segment and the second insertion segment are both consistent.
5. The barrier layer structure with an asymmetric insertion layer according to claim 1 or 4, characterized in that: A transition section is provided between the first insertion segment and the second insertion segment. The top surface of the transition section is connected to the top surfaces of the first insertion segment and the second insertion segment, and the bottom surface of the transition section is connected to the bottom surfaces of the first insertion segment and the second insertion segment, wherein: The top and bottom surfaces of the transition section are horizontal; or The top surface of the transition section extends obliquely upward from the first insertion section to the second insertion section and / or the bottom surface of the transition section extends obliquely downward from the first insertion section to the second insertion section.
6. The barrier layer structure with an asymmetric insertion layer according to claim 5, characterized in that: The bottom surfaces of the transition section, the first insertion section, and the second insertion section are horizontal and coplanar, and the top surface of the transition section extends obliquely upward from the first insertion section to the second insertion section; or The bottom surface of the transition section extends downward at an angle from the first insertion section to the second insertion section, and the top surface of the transition section extends upward at an angle from the first insertion section to the second insertion section; or The bottom surfaces of the transition section and the first insertion section are horizontal and coplanar, the top surfaces of the transition section and the second insertion section are horizontal and coplanar, the bottom surface of the first insertion section is lower than the bottom surface of the second insertion section, and the top surface of the first insertion section is lower than the top surface of the second insertion section.
7. The barrier layer structure with an asymmetric insertion layer according to claim 1, characterized in that: The insertion layer is an AlN insertion layer; or The insertion layer is a composite insertion layer of AlN and AlGaN.
8. The barrier layer structure with an asymmetric insertion layer according to claim 7, characterized in that: When the barrier layer is an AlGaN barrier layer, the Al content in the AlN / AlGaN composite insertion layer is higher than the Al content in the AlGaN barrier layer.
9. The barrier layer structure with an asymmetric insertion layer according to claim 7 or 8, characterized in that: The Al content in the AlN / AlGaN composite insertion layer is 0.35~0.5%.
10. The barrier layer structure with an asymmetric insertion layer according to claim 7, characterized in that: The AlN and AlGaN composite insertion layer includes an AlN sub-insertion layer and an AlGaN sub-insertion layer, which are arranged one above the other.
11. The barrier layer structure with an asymmetric insertion layer according to claim 1, characterized in that: The thickness a of the first insertion segment is 0.5~2 nm; the thickness b of the second insertion segment is 1.5~5 nm.
12. The barrier layer structure with an asymmetric insertion layer according to claim 1, characterized in that: The aforementioned barrier layer is an AlGaN barrier layer, and satisfies: The Al composition in the AlGaN barrier layer is 0.2~0.3; The thickness of the AlGaN barrier layer is 15~30nm.
13. The barrier layer structure with an asymmetric insertion layer according to claim 1 or 12, characterized in that: The insertion layer is located in the lower middle part of the barrier layer, and / or The distance between the bottom surface of the insertion layer and the bottom surface of the barrier layer is 3~8nm.
14. A power device, characterized in that: A barrier layer structure having an asymmetric insertion layer as described in any one of claims 1 to 12.