P-GaN gate HEMT (High Electron Mobility Transistor) anti-radiation device with composite source structure and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor devices, and particularly provides a P-GaN gate HEMT (High Electron Mobility Transistor) anti-radiation device with a composite source structure and a preparation method of the P-GaN gate HEMT anti-radiation device in order to solve the problem of low space radiation resistance of an existing device. The structure comprises a substrate, a buffer layer, a channel layer and a barrier layer from bottom to top, a p-GaN layer is arranged at the middle position above the barrier layer, a grid electrode is arranged above the p-GaN layer, and a source electrode and a drain electrode are arranged on the two sides of the upper surface of the barrier layer respectively; a hole discharge channel is etched and deposited below the source electrode; and a passivation layer is arranged between the gate source and the gate drain. By providing a hole discharge channel, hole accumulation in the device is reduced, so that the single particle resistance and the total dose effect resistance of the device are improved, the radiation resistance advantage of the P-GaN gate HEMT device is further exerted, meanwhile, the problem that other proposed reinforcing structures are high in process difficulty is solved, and the reliability of the device is improved. And therefore, the P-GaN gate HEMT device can be widely applied to the aerospace field.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a P-GaN gate HEMT radiation-resistant device with a composite source structure and a preparation method thereof. Background Art

[0002] With the development of aerospace technology, the requirements for power systems in fields such as space satellites and space exploration are becoming increasingly higher. They need to have characteristics such as high temperature resistance, high power, miniaturization, and adaptability to extreme radiation environments. Gallium nitride (GaN)-based power devices, as the core representative of wide-bandgap semiconductor devices, have higher breakdown voltage, smaller on-resistance, higher high-temperature resistance, and stronger radiation resistance compared to traditional silicon (Si)-based devices, and can meet the needs of the power systems of the new generation of spacecraft. GaN devices mostly use AlGaN / GaN heterojunctions to generate two-dimensional electron gas (2DEG) to form a conductive channel. Therefore, conventional GaN-based HEMTs are depletion-type and require a large bias voltage to turn off the device, resulting in large off-state power consumption and more complex gate drive design.

[0003] Therefore, enhancement-mode devices are often used in circuits, with P-GaN-gate HEMT devices being the primary technology for achieving enhancement-mode performance in commercial devices. However, space contains a variety of high-energy particles, and aerospace systems operating in such an environment are constantly threatened by these particles. When high-energy particles strike a P-GaN-gate HEMT device, they generate a large number of electron-hole pairs. Under the influence of the electric field, electrons are swept toward the drain, which has a high electric field and high potential, while holes accumulate within the device, affecting the internal electric field distribution and generating a localized high field, leading to single-particle burnout. Furthermore, the single-particle reinforcement structure of the currently proposed P-GaN-gate HEMT is relatively complex, making the process implementation very difficult and costly. This limits the application of P-GaN-gate HEMT devices in the aerospace field.

[0004] Existing technology solutions: One existing single-event hardening technology utilizes the built-in electric field formed by the PN junction within the device to confine the large number of electrons generated by heavy ion incidence, reducing the instantaneous electron concentration in the channel and minimizing impact ionization, thereby preventing device burnout. Another method is to construct a channel connected to the source near the gate to dissipate the positive charge induced by the single-event effect (SEB), thereby enhancing the device's radiation resistance.

[0005] Disadvantages of existing technologies: While reported PN junction solutions for improving single-particle resistance can inhibit electron tunneling toward the gate, they cannot effectively absorb holes. A large number of holes accumulate below the gate, potentially modulating the electric field below the gate, increasing off-state leakage, and even causing burnout. Constructing a channel connected to the source near the gate improves single-particle resistance by providing a charge discharge path and reducing charge accumulation within the device. However, the channel connected to the source near the gate changes the device's current path, causing some carriers to pass through the channel. Due to the resistance characteristics of this channel, the overall on-resistance of the device increases. Furthermore, this structure is complex and difficult to optimize. Summary of the Invention

[0006] To comprehensively address the aforementioned issues, the present invention proposes a P-GaN-gate HEMT radiation-resistant device with a composite source structure. A P-type GaN structure, in contact with the buffer layer and source, is employed below the source. This provides a hole discharge channel, reducing hole accumulation within the device. This improves the device's single-event and total-dose resistance capabilities, further leveraging the radiation-resistant advantages of the P-GaN-gate HEMT device. This also addresses the difficulty of fabricating the previously proposed reinforcement structure, enabling widespread application of the P-GaN-gate HEMT device in the aerospace field.

[0007] To achieve the above objectives, the present invention provides, in a first aspect, a P-GaN gate HEMT radiation-resistant device with a composite source structure, comprising, from bottom to top: a substrate, a buffer layer, a channel layer, and a barrier layer; a p-GaN layer disposed at a central position above the barrier layer; a gate disposed above the p-GaN layer; a source and a drain disposed on either side of the upper surface of the barrier layer, wherein the gate-source spacing is smaller than the gate-drain spacing; a hole discharge channel etched and deposited below the source, the hole discharge channel partially contacting the buffer layer and fully contacting the side surfaces of the channel layer and the barrier layer; and a passivation layer disposed between the gate and the source and between the gate and the drain.

[0008] Preferably, the substrate is made of any one of Si, sapphire, SiC or GaN materials; the buffer layer is made of any one of AlN, GaN or AlGaN; the channel layer is made of any one of GaN or AlGaN; the barrier layer is made of any one of AlGaN or AlN; the passivation layer material is made of any one of SiN, SiO2 or Al2O3; and the hole discharge channel is made of any one of P-type GaN, P-type AlGaN and P-type AlN.

[0009] Preferably, the Al component in the material of the barrier layer is higher than that in the channel layer, thereby forming a heterostructure with the channel layer to generate a two-dimensional electron gas conductive channel.

[0010] Preferably, the p-GaN layer is P-type doped GaN with a doping concentration of 1×10 17 cm -3 ~1×10 20 cm -3 , thereby depleting the 2DEG under the gate and realizing an enhancement-mode device; the doping concentration of the hole discharge channel is 1×10 16 cm -3 ~6×10 20 cm -3 .

[0011] Preferably, the source electrode consists of two parts, the first source electrode adopts a Ni / Au metal combination to form an ohmic contact with the hole discharge channel; the second source electrode adopts a Ti / Al / Ni / Au or Ti / Al / Pt / Au metal combination to form an ohmic contact with the barrier layer.

[0012] Preferably, the drain electrode is made of a metal combination of Ti / Al / Ni / Au or Ti / Al / Pt / Au to form an ohmic contact with the barrier layer.

[0013] The gate uses a metal combination of Ni / Au to form a Schottky contact with the p-GaN layer, and the device's on / off is controlled by the gate voltage.

[0014] Preferably, after the hole discharge channel is prepared, a mask is made on the barrier layer to form an ohmic window, and the first source is deposited by electron beam evaporation; then, masks for the second source and drain are respectively made on the barrier layer, and Ti / Al / Ni / Au or Ti / Al / Pt / Au metal is deposited by electron beam evaporation.

[0015] A second aspect of the present invention provides a method for preparing a P-GaN gate HEMT radiation-resistant device with a composite source structure, comprising:

[0016] Prepare the substrate, deposit the buffer layer, channel layer, barrier layer and p-GaN layer in sequence from bottom to top;

[0017] Etching the p-GaN layer outside the P-GaN gate region;

[0018] Etching grooves to deposit hole discharge channels;

[0019] Prepare source electrodes, including source electrode No. 1 and source electrode No. 2;

[0020] preparing a gate;

[0021] preparing a passivation layer;

[0022] Holes are opened in the passivation layer above the source, gate, and drain, and electrodes are led out, ultimately obtaining a P-GaN gate HEMT radiation-resistant device with a composite source structure.

[0023] Preferably, the specific method for depositing the hole discharge channel is:

[0024] An inductively coupled plasma etching process is used to introduce a Cl2 / N2 / O2 mixed gas to etch the p-GaN layer outside the P-GaN area to be retained, exposing the left and right upper surfaces of the barrier layer; then a groove is etched on the side of the barrier layer at the edge closest to the gate, so that the bottom of the groove contacts the buffer layer, and then a mask is made to deposit a hole discharge channel structure in the groove; then, a mask is made on the barrier layer to form an ohmic window, and the No. 1 source is deposited using an electron beam evaporation process; then, masks for the No. 2 source and drain are made on the barrier layer respectively, and Ti / Al / Ni / Au or Ti / Al / Pt / Au metal is deposited using an electron beam evaporation process.

[0025] Preferably, the hole discharge channel structure has a thickness of 40 nm to 100 nm and is subjected to annealing treatment.

[0026] Preferably, after the hole discharge channel is prepared, a mask is made on the barrier layer to form an ohmic window, and the first source is deposited by electron beam evaporation; then, masks for the second source and drain are respectively made on the barrier layer, and Ti / Al / Ni / Au or Ti / Al / Pt / Au metal is deposited by electron beam evaporation.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention proposes a P-GaN gate HEMT radiation-resistant device with a composite source structure. A hole discharge channel is introduced below the source, in contact with the buffer layer and the source. This structure helps to extract holes from the buffer layer below the gate, thereby increasing the barrier height between the source and the channel, suppressing the electron channel below the gate, and reducing the local electric field inside the device. At the same time, a hole discharge channel is provided, thereby reducing the accumulation of charge inside the device, alleviating the local high field, and improving the device's resistance to single-event effects.

[0029] At the same time, fewer electrons are accelerated in the high field region, reducing the deposition of electron-hole pairs and thus reducing the risk of single particle burnout.

[0030] At the same time, the present invention can enhance the device's ability to resist the total dose effect. The total dose effect refers to a radiation effect in which device performance changes are caused by the cumulative radiation-induced charge dose within a certain radiation time. Since a hole discharge channel is provided in the composite source structure, the radiation charge inside the device can be dissipated in time, thereby reducing the risk of the total dose effect.

[0031] Furthermore, while improving the device's resistance to single-event effects and total dose effects, the present invention maintains the same fundamental device characteristics as its unhardened counterpart, including output current density, on-resistance, and breakdown voltage. Furthermore, compared to existing technologies, the present invention offers a simpler device structure, easier processing, and greater ease of manufacturing, promising widespread application in the aerospace field.

[0032] Finally, using Silvaco software, single-event effects were simulated for both conventional P-GaN-gate HEMT devices and P-GaN-gate HEMT devices with a composite source structure. Heavy ions with an LET of 10 pC / μm were incident on the radiation-sensitive locations of both devices. The two device structures, with the exception of the composite source, had identical basic structural parameters. The thickness of the hole discharge channel in the composite source structure was 400 nm, and the doping concentration was 5×10 17 cm -3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0034] In the attached figure:

[0035] Figure 1 Schematic diagram of the P-GaN gate HEMT device structure with a composite source structure;

[0036] Figure 2 Schematic diagram of the process for preparing a P-GaN gate HEMT device with a composite source structure;

[0037] Figure 3 (a) Electron and (b) hole concentration distributions in a conventional P-GaN gate HEMT device under single event effects.

[0038] Figure 4 (a) Electron and (b) hole concentration distributions in a P-GaN gate HEMT device with a composite source structure under single-event effects.

[0039] Figure 5 In the figure, (a) the conventional P-GaN gate HEMT device and (b) the P-GaN gate HEMT device with a composite source structure of the present invention are subjected to the action of a single particle. D Variation with transient time;

[0040] Among them, 1. substrate, 2. buffer layer, 3. channel layer, 4. barrier layer, 5. p-GaN layer, 6. hole discharge channel, 7. source electrode No. 1, 8. source electrode No. 2, 9. drain electrode, 10. gate electrode, 11. passivation layer. DETAILED DESCRIPTION

[0041] The following combination Figure 1-Figure 5 The preferred embodiments of the present invention are described herein. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0042] Example 1:

[0043] like Figure 1 A P-GaN gate HEMT radiation-resistant device with a composite source structure includes, from bottom to top: a substrate 1, a buffer layer 2, a channel layer 3, and a barrier layer 4. A p-GaN layer 5 is provided in the middle position above the barrier layer 4, a gate 10 is provided above the p-GaN layer 5, and a source and a drain 9 are provided on both sides of the upper surface of the barrier layer 4, respectively. The source includes a first source 7 and a second source 8. The first source 7 uses Ni / Au to form an ohmic contact with the hole discharge channel, while the second source 8 uses a Ti / Al / Ni / Au or Ti / Al / Pt / Au metal combination to form an ohmic contact with the n-type AlGaN material. The gate-source spacing (the gate-source spacing is the distance between the gate 10 and the source) is smaller than the gate-drain spacing (the gate-drain spacing is the distance between the gate 10 and the drain 9); a hole discharge channel 6 is etched and deposited below the source 10, and the hole discharge channel 6 is partially in contact with the buffer layer 2 and is in full contact with the side surfaces of the channel layer 3 and the barrier layer 4; a passivation layer 11 is provided between the gate and source (the gate 10 and the source) and between the gate and drain (the gate 10 and the drain 9).

[0044] Furthermore, the hole discharge channel is any one of P-type GaN, P-type AlGaN or P-type AlN.

[0045] Furthermore, the thickness of the hole discharge channel 6 can be adjusted according to the situation, and the length of the source electrode can be equal to the drain electrode 9, or slightly larger than the length of the drain electrode 9 (reducing the thickness of the hole discharge channel will increase the single-particle burnout voltage, but the reduction in thickness will introduce some negative effects, such as increased leakage current, because its thickness can be adjusted according to the situation; because the source electrode consists of two parts, appropriately adjusting the length of the source electrode can better adapt to the limitations of process conditions).

[0046] The substrate 1 may be made of any one of Si, sapphire, SiC or GaN materials.

[0047] The buffer layer 2 can be made of any one of AlN, GaN or AlGaN.

[0048] The channel layer 3 is made of either GaN or AlGaN.

[0049] The barrier layer 4 is made of either AlGaN or AlN; the Al composition is higher than that in the channel layer 3, thereby forming a heterostructure with the channel layer 3 to generate a two-dimensional electron gas conductive channel.

[0050] The p-GaN layer 5 is P-type doped GaN with a doping concentration of 1×10 17 cm -3 ~1×10 20 cm -3 , thereby depleting the 2DEG under the gate and realizing an enhancement-mode device.

[0051] The hole discharge channel is any one of P-type GaN, P-type AlGaN and P-type AlN, and its doping concentration is 1×10 16 cm -3 ~6×10 20 cm -3 .

[0052] The source electrode consists of two parts. The first source electrode 7 uses a Ni / Au metal combination to form an ohmic contact with the hole discharge channel, and the second source electrode 8 uses a Ti / Al / Ni / Au metal combination to form an ohmic contact with the barrier layer.

[0053] The drain electrode 9 is generally made of a metal combination of Ti / Al / Ni / Au or Ti / Al / Pt / Au to ensure an ohmic contact with the barrier layer 4 .

[0054] The gate 10 is made of a metal combination of Ni / Au and forms a Schottky contact with the p-GaN layer 5 , thereby controlling the switching of the device by gate voltage.

[0055] The doping concentration of the hole discharge channel 6 below the source is generally 1×10 16 cm -3 ~1×10 20 cm -3 .

[0056] The material of the passivation layer 11 can be any one of SiN, SiO2 or Al2O3.

[0057] The principle based on the structure of the present invention is:

[0058] When high-energy particles are incident on a GaN device, they collide with the semiconductor lattice, causing a large number of electron-hole pairs to be generated inside the device and forming ionization tracks of heavy ions. A large number of electron-hole pairs produce ionized charge deposition at sensitive positions of the device, affecting the electric field distribution inside the device, and causing a sharp increase in current under the action of the electric field, resulting in single-particle burnout. In order to reduce the deposition of electron-hole pairs, the present invention uses a hole discharge channel 6 connected to the source under the source to realize a hole discharge channel, the bottom of which is in contact with the buffer layer 2. This structure helps to extract holes from the buffer layer 2 under the gate 10, thereby increasing the barrier height between the source and the channel layer 3, suppressing the electron channel under the gate 10, and reducing the local electric field inside the device. At the same time, fewer electrons are accelerated in the high-field region, thereby reducing the risk of single-particle burnout.

[0059] Example 2:

[0060] Figure 2 The present invention provides a schematic flow chart of a method for preparing a P-GaN gate HEMT radiation-resistant device with a composite source structure.

[0061] A method for preparing a P-GaN gate HEMT radiation-resistant device with a composite source structure, comprising:

[0062] S1: First, select a substrate 1 material, which can be Si, SiC, sapphire, or GaN. Substrate 1 is pretreated and heat-treated. Substrate 1 is immersed in a hydrofluoric acid (HF) solution for 1 minute. Ultrasonic cleaning is then performed in acetone, anhydrous ethanol, and deionized water for 10 minutes each to eliminate dangling bonds on the surface of substrate 1. After cleaning and drying, substrate 1 is heat-treated in a hydrogen (H2) atmosphere for 10 minutes at 1050°C to remove surface contaminants. Then, a metal organic chemical vapor deposition (MOCVD) process is used to deposit a buffer layer 2 with a thickness of 0.5μm to 3μm. The buffer layer 2 material can be GaN, AlN or AlGaN. During the deposition of the buffer layer 2, the reaction chamber pressure in the MOCVD process is 10Torr to 100Torr, the gallium (Ga) flow rate is 50μmol / min to 100μmol / min, the ammonia flow rate is 3000sccm to 6000sccm, the hydrogen flow rate is 1000sccm to 2000sccm, and the temperature is 900°C.

[0063] S2: Depositing a 50 nm to 500 nm thick channel layer 3 on the buffer layer 2 using the MOCVD process. The material of the channel layer 3 can be one of GaN, AlN, and AlGaN. The MOCVD process parameters are: a reaction chamber pressure of 10 Torr to 100 Torr, a temperature of 900°C, a Ga source flow rate of 50 μmol / min to 100 μmol / min, an ammonia flow rate of 3000 sccm to 6000 sccm, and a hydrogen flow rate of 1000 sccm to 2000 sccm.

[0064] S3: Continue to use MOCVD process to deposit barrier layer 4 on channel layer 3. The barrier layer 4 material can be AlGaN or AlN material. If Al x Ga (1-x) N material, wherein the value of x is between 0.1 and 0.3, and the thickness of the barrier layer 4 is 10 nm to 50 nm. During the deposition of the barrier layer 4, the reaction chamber pressure in the MOCVD process is 10 Torr to 100 Torr, the Al source flow rate is 10 μmol / min to 30 μmol / min, the Ga source flow rate is 30 μmol / min to 90 μmol / min, the ammonia flow rate is 3000 sccm to 6000 sccm, the hydrogen flow rate is 1000 sccm to 2000 sccm, and the temperature is 900°C;

[0065] S4: A p-GaN layer 5 with a thickness of 50nm to 200nm is deposited on the barrier layer 4 using an MOCVD process to obtain an epitaxial wafer. The MOCVD process parameters are: a reaction chamber pressure of 10Torr to 100Torr, a temperature of 900°C, and a Ga source with a flow rate of 30μmol / min to 90μmol / min, a hydrogen flow rate of 1000sccm to 2000sccm, and an ammonia flow rate of 3000sccm to 6000sccm into the reaction chamber. Thus, the desired epitaxial wafer is obtained (the epitaxial wafer is the epitaxial wafer prepared by MOCVD or other methods in steps S1-S4, which, from bottom to top, consists of a substrate, a buffer layer, a channel layer, a barrier layer, and a p-GaN layer).

[0066] S5: Soak the epitaxial wafer in an organic solvent (such as acetone or isopropyl alcohol) and use the dissolving power of the organic solvent to remove organic matter and grease on the surface. Use an organic alkaline cleaning solution (such as tetramethylammonium hydroxide, TMAH) to clean the surface of the epitaxial wafer to remove surface particles. Then rinse with ultrapure water to remove the residual organic alkaline cleaning solution. Then use deionized water and ultrasonic cleaning to remove residual chemicals on the surface. Finally, use hot nitrogen to purge the surface of the epitaxial wafer to quickly remove moisture;

[0067] S6: Using an inductively coupled plasma (ICP) etching process, a Cl2 / N2 / O2 mixed gas is introduced to etch the p-GaN 5 layer outside the P-GaN region to be retained, exposing the upper left and right surfaces of the barrier layer 4. Then, a groove is etched on the side of the barrier layer 4 closest to the gate 10, so that the bottom of the groove contacts the buffer layer 2. Figure 1 The hole discharge channel region is shown in the figure. Then, a mask is made and a hole discharge channel 6 structure is deposited in the groove using a MOCVD process or other methods. The hole discharge channel is any one of P-type GaN, P-type AlGaN and P-type AlN, with a thickness of 40nm to 100nm and a doping concentration of 1×10 16 ~6×10 20 cm -3 , and perform rapid annealing at high temperature (750℃~800℃, 20min~25min) to obtain good crystal quality;

[0068] S7: Continue to make a mask on the barrier layer 4 to form an ohmic window, place it in an electron beam (E-Beam) evaporation device, and use the electron beam evaporation process to deposit the first source. The first source 7 uses a Ni / Au metal combination and is annealed at 500°C to 600°C for 5 minutes to ensure that it forms an ohmic contact with the hole discharge channel 6. Then, masks for the second source 8 and drain 9 are made on the barrier layer 4 respectively, and Ti / Al / Ni / Au or Ti / Al / Pt / Au metal is deposited using the electron beam evaporation process. The electron beam evaporation process rate is 0.1nm / s, and annealed at 850°C for 30s to ensure that it forms a good ohmic contact with the barrier layer 4.

[0069] S8: A mask is made on the barrier layer 4 to form a gate window. The sample with the window is placed in an electron beam evaporation reaction chamber. Using nickel and gold targets with a purity of 99.999%, metal Ni / Au is deposited in the gate window by electron beam evaporation as a gate 10, wherein the thickness of Ni is 20nm to 30nm, and the thickness of Au is 40nm to 70nm.

[0070] S9: A plasma-enhanced chemical vapor deposition (PECVD) process is used to deposit a passivation layer with a thickness of 100nm to 400nm on the upper portion of the barrier layer 4, the source electrode, the drain electrode 9, and the gate electrode 10. The passivation layer 11 can be made of SiN, SiO2, or Al2O3. The pressure in the reaction chamber is 0.5Pa to 30Pa, and the temperature is 200°C to 350°C. Silane and nitrous oxide gas or silane and ammonia gas are introduced simultaneously. Finally, holes are opened in the passivation layer 11 above the source electrode, the gate electrode 10, and the drain electrode 9 to lead out the electrodes. Finally, a P-GaN gate HEMT radiation-resistant device with a composite source structure is obtained.

[0071] like Figure 3 For traditional P-GaN gate HEMT devices, V DS The simulation results of the electron and hole concentration distribution under the action of a single event at 300V are shown in the figure. As can be seen from the figure, after the single event effect occurs, the electron and hole concentrations inside the traditional P-GaN gate HEMT device are very high, and the current is at a high level and cannot be restored to a lower value, further causing the device to burn out.

[0072] like Figure 4 The figure shows the P-GaN gate HEMT device with a composite source structure at V DS The simulation results of the electron and hole concentration distribution under the action of a single event at 300V are shown. As can be seen from the figure, after the single event effect, the electron and hole concentrations inside the P-GaN gate HEMT device with a composite source structure are both at a low state, and the current can be restored to a low value. This indicates that the electron-hole pairs generated by irradiation are absorbed, and the P-GaN gate HEMT device with a composite source structure has returned to normal without single event burnout.

[0073] Figure 5 (a) and (b) show the functional relationship between the drain current and transient time of the two devices under different working biases. After heavy ion impact, the single event burnout voltage V of the traditional P-GaN gate HEMT device and the P-GaN gate HEMT device with a composite source structure SEB They are 285V and 385V respectively, indicating that the device of the present invention can effectively improve the single event burnout threshold voltage and the single event burnout resistance of the device.

[0074] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A P-GaN gate HEMT radiation-resistant device with a composite source structure, characterized in that: From bottom to top, it includes: a substrate, a buffer layer, a channel layer and a barrier layer. A p-GaN layer is arranged in the middle position above the barrier layer, a gate is arranged above the p-GaN layer, and a source and a drain are arranged on both sides of the upper surface of the barrier layer, wherein the gate-source spacing is smaller than the gate-drain spacing; a hole discharge channel is etched and deposited below the source, which is in partial contact with the buffer layer and in full contact with the side surfaces of the channel layer and the barrier layer; a passivation layer is provided between the gate and the source and between the gate and the drain.

2. The P-GaN gate HEMT radiation-resistant device with a composite source structure according to claim 1, characterized in that: The substrate is made of any one of Si, sapphire, SiC or GaN materials; the buffer layer is made of any one of AlN, GaN or AlGaN; the channel layer is made of any one of GaN or AlGaN; the barrier layer is made of any one of AlGaN or AlN; the passivation layer material is made of any one of SiN, SiO2 or Al2O3; and the hole discharge channel is made of any one of P-type GaN, P-type AlGaN and P-type AlN.

3. The P-GaN gate HEMT radiation-resistant device with a composite source structure according to claim 2, characterized in that: The Al component in the material of the barrier layer is higher than that in the channel layer, thereby forming a heterostructure with the channel layer to generate a two-dimensional electron gas conductive channel.

4. The P-GaN gate HEMT radiation-resistant device with a composite source structure according to claim 3, characterized in that: The p-GaN layer is P-type doped GaN with a doping concentration of 1×10 17 cm -3 ~1×10 20 cm -3 , to deplete the 2DEG under the gate to realize an enhancement-mode device; the doping concentration of the hole discharge channel is 1×10 16 cm -3 ~6×10 20 cm -3 .

5. The P-GaN gate HEMT radiation-resistant device with a composite source structure according to claim 4, characterized in that: The source electrode consists of two parts. The first source electrode uses a Ni / Au metal combination to form an ohmic contact with the hole discharge channel; the second source electrode uses a Ti / Al / Ni / Au or Ti / Al / Pt / Au metal combination to form an ohmic contact with the barrier layer.

6. The P-GaN gate HEMT radiation-resistant device with a composite source structure according to claim 5, characterized in that: The drain electrode uses a metal combination of Ti / Al / Ni / Au or Ti / Al / Pt / Au to form an ohmic contact with the barrier layer; The gate uses a metal combination of Ni / Au to form a Schottky contact with the p-GaN layer.

7. A method for preparing a P-GaN gate HEMT radiation-resistant device with a composite source structure, characterized in that: include: Prepare the substrate, deposit the buffer layer, channel layer, barrier layer and p-GaN layer in sequence from bottom to top; Etching the p-GaN layer outside the P-GaN gate region; Etching grooves to deposit hole discharge channels; Prepare source electrodes, including source electrode No. 1 and source electrode No. 2; preparing a gate; preparing a passivation layer; Holes are opened in the passivation layer above the source, gate, and drain, and electrodes are led out, ultimately obtaining a P-GaN gate HEMT radiation-resistant device with a composite source structure.

8. The method for preparing a P-GaN gate HEMT radiation-resistant device with a composite source structure according to claim 7, characterized in that: The specific method of depositing the hole discharge channel is: The p-GaN layer outside the P-GaN area to be retained is etched to expose the left and right upper surfaces of the barrier layer; then a groove is etched on the side of the barrier layer closest to the gate, so that the bottom of the groove contacts the buffer layer. Then, a mask is made and a hole discharge channel structure is deposited in the groove.

9. The method for preparing a P-GaN gate HEMT radiation-resistant device with a composite source structure according to claim 8, characterized in that: The hole discharge channel structure has a thickness of 40 nm to 100 nm and is subjected to annealing treatment.

10. The method for preparing a P-GaN gate HEMT radiation-resistant device with a composite source structure according to claim 9, characterized in that: After the hole discharge channel is prepared, a mask is made on the barrier layer to form an ohmic window, and the No. 1 source electrode is deposited using an electron beam evaporation process; then, masks for the No. 2 source electrode and drain electrode are made on the barrier layer respectively, and Ti / Al / Ni / Au or Ti / Al / Pt / Au metal is deposited using an electron beam evaporation process.

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