A high linearity radio frequency AlGaN / GaN device and its fabrication method

Abstract

This invention discloses a method for fabricating high-linearity radio frequency AlGaN / GaN devices: Step 1, selecting AlGaN / GaN and SiC as substrate materials, and depositing a SiN thin film using PECVD; Step 2, exposing interconnect contact holes using photolithography, then etching the SiN and AlGaN barrier layers respectively, and opening the interconnect contact holes in the drift region; Step 3, growing a polycrystalline silicon thin film using LPCVD and performing N-type doping; Step 4, exposing a stacked array structure in the gate-drain region on the interconnect contact holes using photolithography, and... RIE is used to etch the exposed N+Polysi or N+Ge and the underlying SiN to obtain a stacked array pattern along the gate width direction; Step 5, photolithography is performed to expose the source and drain patterns of the ohmic contacts, Ti / Al / Ni / Au is evaporated with an electron beam, and after resist removal and rapid thermal annealing, the source-level ohmic contacts of the device are formed; Step 6, photolithography is performed to expose the Schottky gate pattern, Ni / Au is evaporated with an electron beam to fabricate an RF AlGaN / GaN device with a dual-channel stacked structure of the gate and drain regions.

Description

Technical Field

[0001] This invention relates to the field of semiconductor devices, and more specifically to a high linearity radio frequency AlGaN / GaN device and its fabrication method. Background Technology

[0002] GaN, a third-generation semiconductor, possesses a wide bandgap (3.4 eV), high breakdown field strength (3 MV / cm), and high electron mobility (1500 cm⁻¹) at room temperature. 2 / (V·s)), extremely high peak electron velocity (3×10⁻⁶ / (V·s)), 7 (cm / s) and high two-dimensional electron gas concentration (2×10) 13 / cm 2 AlGaN / GaN HEMTs power devices are gradually replacing RF-LDMOS and GaAs power devices, becoming the preferred microwave power devices for T / R modules in phased array radars. On the other hand, with the urgent need for massive data broadband transmission in 5G communication, AlGaN / GaN HEMTs devices, which operate at high frequencies and have high power density advantages, will play a significant role in civilian wireless communication. However, considering the new applications of 5G millimeter waves and the drawback of GaAs's low power density, microwave RF GaN devices urgently need to overcome technical bottlenecks such as high frequency, high linearity, and high current drive to meet the high power density and miniaturization requirements of application terminals and relay layer equipment with fewer GaN microwave devices.

[0003] High linearity and high power density applications for 5G mobile terminals have become a research hotspot in GaN millimeter-wave devices in recent years. Researchers have successively explored material epitaxy and novel device structures, proposing master-slave dual-channel and FinFET structures to linearize the DC-V characteristics of AlGaN / GaN HEMTs devices to meet the application requirements of 5G communication. Master-slave dual-channel has become one of the more mature linearizable device technologies for GaN microwave devices. FinFET devices, due to the need to form a fin-like structure, suffer from sidewall defects formed by etching, which significantly affect the device's RF characteristics, thus limiting their application to some extent. Summary of the Invention

[0004] This invention is made to solve the above-mentioned problems, and its purpose is to provide a high linearity radio frequency AlGaN / GaN device and its fabrication method.

[0005] This invention provides a method for fabricating a high-linearity radio frequency AlGaN / GaN device, characterized by the following steps: Step 1, selecting AlGaN, GaN, and SiC as substrate materials, and depositing a SiN thin film on the substrate material using chemical vapor deposition (PECVD) to obtain sample A; Step 2, using photolithography to expose interconnect contact holes on sample A, then etching the SiN and AlGaN barrier layers respectively, and opening the interconnect contact holes in the drift region; Step 3, growing a polycrystalline silicon thin film using low-pressure chemical vapor deposition (LPCVD), and performing ion implantation of phosphorus atoms to either N-type doping and annealing the polycrystalline silicon thin film to obtain N+ Polysi, or forming an N-type Ge thin film using molecular beam epitaxy; Step 4, using photolithography... In step 5, a stacked array structure is exposed in the gate-drain region on the interconnect contact hole. The exposed N+Polysi or N+Ge and the underlying SiN masking layer are etched by reactive ion etching (RIE) to obtain a stacked array pattern along the gate width direction, which contacts the drain region, resulting in sample B. In step 6, sample B is photolithographically etched to expose the source-drain pattern of the ohmic contact. Ti, Al, Ni and Au are evaporated by electron beam. After resist removal and rapid thermal annealing, the source-level ohmic contact of the device is formed, resulting in sample C. In step 7, sample C is photolithographically etched to expose the pattern of the Schottky gate. Ni and Au are evaporated by electron beam. After resist removal, the Schottky gate is obtained, and finally, an RF AlGaN / GaN device with a dual-channel stacked structure in the gate-drain region is fabricated.

[0006] The method for fabricating a high-linearity radio frequency AlGaN / GaN device provided by this invention may also have the following feature: in step 1, AlGaN and GaN are positioned above SiC. The thickness of the SiN thin film is 90–110 nm.

[0007] The method for fabricating a high-linearity radio frequency AlGaN / GaN device provided by the present invention may also have the following feature: wherein, in step 2, the interconnection contact hole is an interconnection contact hole between N+Polysi or N+Ge and AlGaN / GaN two-dimensional electron gas.

[0008] The method for fabricating a high-linearity radio frequency AlGaN / GaN device provided by the present invention may also have the following feature: in step 3, the thickness of the polycrystalline silicon thin film or Ge thin film is 0.05 to 0.5 μm.

[0009] The method for fabricating high-linearity radio frequency AlGaN / GaN devices provided by this invention may also have the following feature: in step 3, the sheet resistance is controlled at 50–120 Ω / □ during the N-type doping process. N+Ge is formed using molecular beam epitaxy (MBE).

[0010] The fabrication method of the high linearity radio frequency AlGaN / GaN device provided by the present invention may also have the following feature: in step 3, N+Polysi or N+Ge is positively charged, and the upper and lower surfaces of AlGaN are negatively charged and positively charged, respectively.

[0011] The fabrication method of the high linearity radio frequency AlGaN / GaN device provided by the present invention may also have the following feature: in step 4, the stacked array structure is an N-type polysilicon / AlGaN / GaN or an N+Ge / AlGaN / GaN stacked array structure.

[0012] The method for fabricating high linearity radio frequency AlGaN / GaN devices provided by this invention may also have the following feature: in step 5, the rapid thermal annealing temperature is 840-860°C and the time is 50-70s.

[0013] The fabrication method of the high linearity radio frequency AlGaN / GaN device provided by the present invention may also have the following feature: in step 6, the dual-channel stacked structure is an N-type polysilicon / AlGaN / GaN or an N+Ge / AlGaN / GaN dual-channel stacked structure.

[0014] This invention provides a high-linearity radio frequency AlGaN / GaN device, characterized by comprising: a substrate material made of AlGaN / GaN on SiC; N-type polycrystalline silicon or N-type Ge disposed above the substrate material; and a source electrode disposed above the substrate material. The high-linearity radio frequency AlGaN / GaN device is fabricated using the aforementioned method.

[0015] The role and effect of invention

[0016] According to the fabrication method of the high linearity radio frequency AlGaN / GaN device of the present invention, the specific process is as follows: Step 1, selecting AlGaN, GaN, and SiC as substrate materials, and depositing SiN thin films on the substrate materials using PECVD to obtain sample A; Step 2, using photolithography, exposing interconnect contact holes on sample A, then etching SiN and AlGaN barrier layers respectively, and opening interconnect contact holes in the drift region; Step 3, growing polycrystalline silicon thin films using PECVD, performing ion implantation of phosphorus atoms, performing N-type doping on the polycrystalline silicon thin films and annealing to obtain N-type polycrystalline silicon, or forming N-type Ge thin films using molecular beam epitaxy; Step 4, using photolithography, exposing interconnect contact holes... Step 5: Photolithography is performed on sample B to expose the stacked array structure of the gate and drain regions. Reactive ion etching is used to etch the exposed N-type polysilicon or N+Ge and the underlying SiN masking layer to obtain a stacked array pattern along the gate width direction, resulting in sample B. Step 6: Photolithography is performed on sample B to expose the source and drain patterns of the ohmic contacts. Ti, Al, Ni and Au are evaporated by electron beam. After resist removal and rapid thermal annealing, the source-level ohmic contacts of the device are formed, resulting in sample C. Step 7: Photolithography is performed on sample C to expose the Schottky gate pattern. Ni and Au are evaporated by electron beam. After resist removal, the Schottky gate is obtained, and finally, an RF AlGaN / GaN device with a dual-channel stacked structure of the gate and drain regions is fabricated.

[0017] In fact, the nonlinear mechanism of GaN devices is quite complex, manifested both in the higher-order components of the current at the channel and in the nonlinear capacitance effect during the switching between amplification and cutoff states. Therefore, this invention proposes a novel stacked channel device structure in the drift region constructed from N+ type polysilicon or, more mobile N+ type Ge and AlGaN / GaN.

[0018] Furthermore, the new capacitance effects of N+polySi / AlGaN / GaN and N+Ge / AlGaN / GaN due to the new structure have a capacitance homogenization mechanism. This mechanism not only reconstructs the original nonlinear capacitance in the device drift region, but also provides a new current transport path for the device and obtains a lower gate-drain on-resistance. As a result, GaN devices have higher power gain and better linearized RF characteristics.

[0019] Furthermore, this invention proposes an N+ type doped polysilicon structure with ion-implanted phosphorus impurities (40–60 keV, 1e14–2e15 / cm2), forming a stacked current channel of N+ type polysi polysilicon and AlGaN / GaN in the source / drain region. The length of the N+ type polysi polysilicon (Lgd, polysi: 1–5 μm) and the thickness of the n-type polysilicon are 0.05–0.5 μm, and its sheet resistance can be controlled at 50–120 Ω / □, significantly lower than the sheet resistance of the AlGaN / GaN two-dimensional electron gas (300–400 Ω / □) with a quantum well width of approximately 2 nm. The design of radio frequency devices can be realized by utilizing two channels with different sheet resistances. The N+ type Ge structure can be formed on the AlGaN / GaN heterojunction through MBE epitaxy.

[0020] Furthermore, N+-type doped polysilicon structures or N+-type Ge structures form arrayed strip structures. The newly added N+Polysi / AlGaN / GaN and N+Ge / AlGaN / GaN array structures modulate the original 2D electric field of the gate-drain structure along the gate width direction, releasing the high electric field at the gate edge, reducing Miller capacitance, and resulting in better linearity of the RF device. Moreover, the width ratio of the Ge and Polysi array strips to the AlGaN / GaN is 5:1 to 10:1, achieving complete charge sharing of the depletion layer along the gate width direction, reducing Miller capacitance, and improving nonlinearity.

[0021] In summary, conventional AlGaN / GaN heterojunction structures are composed of a thin barrier with a thickness of approximately 20 nm, resulting in strong IV nonlinearity in GaN RF devices. Therefore, we propose using N+Polysi or N+Ge doped thin films to construct N+Polysi / AlGaN / GaN and N+Ge / AlGaN / GaN array structures in the gate-drain drift region to reshape conventional AlGaN / GaN devices and obtain better microwave power characteristics. This invention adds N+Polysi / AlGaN / GaN and N+Ge / AlGaN / GaN stacked structures, forming two current paths, significantly reducing gate-source resistance, improving the efficiency of GaN RF devices, reducing knee voltage, and increasing output power. The N+Polysi / AlGaN / GaN structure of this invention... The N+Ge / AlGaN / GaN stacked structure adds an electric field along the vertical direction between N+Polysi or N+ and AlGaN / GaN, weakening the two-dimensional electric field distribution between the gate and drain, thus improving the device's breakdown characteristics, reducing the gate-drain spacing Lgd and on-resistance Rds, and enhancing the device's RF performance. Finally, the array-type N+Polysi / AlGaN / GaN and N+Ge / AlGaN / GaN stacked structures of this invention can improve the electric field distribution along the gate width, reducing the gate-drain spacing Lgd and on-resistance Rd, making the Miller capacitance Cgd more uniform, and improving the high linearity and power performance of the RF device. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of step S1 in the high linearity radio frequency AlGaN / GaN device fabrication method in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram illustrating step S2 of the high linearity radio frequency AlGaN / GaN device fabrication method in an embodiment of the present invention, wherein... Figure 2 (a) is a cross-sectional view. Figure 2 (b) is a top view;

[0024] Figure 3 This is a schematic diagram illustrating steps S3 to S4 of the high-linearity radio frequency AlGaN / GaN device fabrication method in an embodiment of the present invention, wherein... Figure 3 (a) is a cross-sectional view. Figure 3 (b) is a top view;

[0025] Figure 4 This is a schematic diagram of step S5 in the high linearity radio frequency AlGaN / GaN device fabrication method of the present invention, wherein... Figure 4 (a) is a cross-sectional view. Figure 4 (b) is a top view;

[0026] Figure 5 This is a schematic diagram of step S6 in the high linearity radio frequency AlGaN / GaN device fabrication method of the present invention, wherein... Figure 5 (a) is a cross-sectional view. Figure 5 (b) is a top view. Detailed Implementation

[0027] To make the technical means, creative features, objectives and effects of this invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate a method for fabricating a high linearity radio frequency AlGaN / GaN device according to this invention.

[0028] This embodiment provides a method for fabricating a high-linearity radio frequency AlGaN / GaN device. Specifically, it includes the following steps:

[0029] Figure 1 This is a schematic diagram of step S1 in the high linearity radio frequency AlGaN / GaN device fabrication method in an embodiment of the present invention.

[0030] like Figure 1 As shown, in step S1, AlGaN / GaN on SiC is selected as the substrate material 10, and a 100nm SiN thin film is deposited by PECVD. The substrate material 10 consists of a SiC layer 11, a GaN layer 12, and an AlGaN layer 13 from bottom to top.

[0031] Figure 2 This is a schematic diagram illustrating step S2 of the high linearity radio frequency AlGaN / GaN device fabrication method in an embodiment of the present invention, wherein... Figure 2 (a) is a cross-sectional view. Figure 2 (b) is a top view.

[0032] like Figure 2 As shown, in step S2, a photolithography process is used to expose the interconnect contact hole pattern between N+Polysi and AlGaN / GaN two-dimensional electron gas. Then, the SiN and AlGaN barrier layers are etched respectively, and the interconnect contact hole between N-type polysilicon (N+Polysi) and AlGaN / GaN two-dimensional electron gas is opened in the drift region.

[0033] Figure 3 This is a schematic diagram illustrating steps S3 to S4 of the high-linearity radio frequency AlGaN / GaN device fabrication method in an embodiment of the present invention, wherein... Figure 3 (a) is a cross-sectional view. Figure 3 (b) is a top view.

[0034] like Figure 3As shown, in step S3, a polycrystalline silicon thin film with a thickness of 0.1 μm is grown using PECVD, and phosphorus atoms are implanted by ion implantation. The polycrystalline silicon thin film is then N-type doped and annealed to obtain an N+ Polysi layer 20, the sheet resistance of which can be controlled between 50 and 120 Ω / □. The N-type Ge thin film can be formed by MBE epitaxy.

[0035] At this point, the N+Polysi layer 20 is positively charged, and the upper and lower surfaces of AlGaN are negatively charged and positively charged, respectively. The two semiconductor materials form a charge balance along the Y direction, thus releasing the surface electric field concentration along the X axis to a certain extent.

[0036] In step S4, a photolithography process is used to expose an N+Polysi / AlGaN / GaN stacked array structure in the gate-drain region of the interconnect contact hole. Then, a re-etching process (RIE) is used to etch the exposed N+Polysi layer 20 and the underlying SiN masking layer, resulting in a stacked array pattern along the gate width direction, which contacts the drain region. At this point, two currents, I1 and I2, are formed.

[0037] Figure 4 This is a schematic diagram of step S5 in the high linearity radio frequency AlGaN / GaN device fabrication method of the present invention, wherein... Figure 4 (a) is a cross-sectional view. Figure 4 (b) is a top view.

[0038] like Figure 4 As shown, in step S5, photolithography is performed to expose the source and drain patterns of the ohmic contacts. Ti / Al / Ni / Au electron beam evaporation is then performed, followed by resist removal and rapid thermal annealing to form the source-level ohmic contacts of the device. The annealing conditions are 850 degrees Celsius for 60 seconds, forming the source electrode 30. The source electrode 30 includes a Ti layer 31, an Al layer 32, a Ni layer 33, and an Au layer 34 formed sequentially from bottom to top. At this point, a dual-channel current circuit composed of N-type polysilicon and AlGaN / GaN is formed.

[0039] Figure 5 This is a schematic diagram of step S6 in the high linearity radio frequency AlGaN / GaN device fabrication method of the present invention, wherein... Figure 5 (a) is a cross-sectional view. Figure 5 (b) is a top view.

[0040] like Figure 5 As shown, in step S6, photolithography is performed to expose the pattern of the Schottky gate, Ni / Au is evaporated by electron beam, and after resist removal and peeling, the Schottky gate is obtained, and finally an RF AlGaN / GaN device with a gate-drain region N+Polysi / AlGaN / GaN dual-channel stacked structure is fabricated.

[0041] At this point, the electric field can be released along the Z-axis (i.e., the grid width direction), thus releasing the surface electric field concentration along the X-axis to a certain extent.

[0042] The role and effect of the embodiments

[0043] According to the fabrication method of the high linearity radio frequency AlGaN / GaN device involved in this embodiment, the specific process is as follows: Step 1, select AlGaN, GaN, and SiC as substrate materials, and deposit SiN thin films on the substrate materials using PECVD to obtain sample A; Step 2, use photolithography to expose interconnect contact holes on sample A, then etch the SiN and AlGaN barrier layers respectively, and open the interconnect contact holes in the drift region; Step 3, use PECVD to grow polycrystalline silicon thin films, and perform ion implantation of phosphorus atoms to perform N-type doping on the polycrystalline silicon thin films and anneal to obtain N-type polycrystalline silicon, or form N-type Ge thin films using molecular beam epitaxy; Step 4, use photolithography to create the gate drain on the interconnect contact holes. Step 1: A stacked array structure is exposed in the region. Reactive ion etching is used to etch the exposed N-type polysilicon or N+Ge and the underlying SiN masking layer to obtain a stacked array pattern along the gate width direction, which contacts the drain region, resulting in sample B. Step 5: Sample B is photolithographically etched to expose the source-drain pattern of ohmic contacts. Ti, Al, Ni, and Au are evaporated with an electron beam. After resist removal and rapid thermal annealing, the source-level ohmic contacts of the device are formed, resulting in sample C. Step 6: Sample C is photolithographically etched to expose the Schottky gate pattern. Ni and Au are evaporated with an electron beam. After resist removal, the Schottky gate is obtained, and finally, an RF AlGaN / GaN device with a dual-channel stacked structure of gate and drain regions is fabricated.

[0044] In fact, the nonlinear mechanism of GaN devices is quite complex, manifested both in the higher-order components of the current at the channel and in the nonlinear capacitance effect during the switching between amplification and cutoff states. Therefore, this embodiment proposes a novel stacked channel device structure in the drift region constructed from N+ type polysilicon or, more mobile N+ type Ge and AlGaN / GaN.

[0045] Furthermore, the new capacitance effects of N+polySi / AlGaN / GaN and N+Ge / AlGaN / GaN due to the new structure have a capacitance homogenization mechanism. This mechanism not only reconstructs the original nonlinear capacitance in the device drift region, but also provides a new current transport path for the device and obtains a lower gate-drain on-resistance. As a result, GaN devices have higher power gain and better linearized RF characteristics.

[0046] Furthermore, this embodiment proposes an N+ type doped polysilicon structure with ion-implanted phosphorus impurities (40–60 keV, 1e14–2e15 / cm2), forming a stacked current channel of N+ type polysi polysilicon and AlGaN / GaN in the source / drain region. The length of the N+ type polysi polysilicon (Lgd, polysi: 1–5 μm) and the thickness of the n-type polysilicon are 0.05–0.5 μm, and its sheet resistance can be controlled at 50–120 Ω / □, which is significantly lower than the sheet resistance of the AlGaN / GaN two-dimensional electron gas (300–400 Ω / □) with a quantum well width of approximately 2 nm. The design of radio frequency devices can be realized by using two channels with different sheet resistances. The N+ type Ge structure can be formed on the AlGaN / GaN heterojunction through MBE epitaxy.

[0047] Furthermore, N+-type doped polysilicon structures or N+-type Ge structures form arrayed strip structures. The newly added N+Polysi / AlGaN / GaN and N+Ge / AlGaN / GaN array structures modulate the original 2D electric field of the gate-drain structure along the gate width direction, releasing the high electric field at the gate edge, reducing Miller capacitance, and resulting in better linearity of the RF device. Moreover, the width ratio of the Ge and Polysi array strips to the AlGaN / GaN is 5:1 to 10:1, achieving complete charge sharing of the depletion layer along the gate width direction, reducing Miller capacitance, and improving nonlinearity.

[0048] In summary, conventional AlGaN / GaN heterojunction structures are composed of a thin barrier with a thickness of approximately 20 nm, resulting in strong IV nonlinearity in GaN RF devices. Therefore, we propose using N+Polysi or N+Ge doped thin films to construct N+Polysi / AlGaN / GaN and N+Ge / AlGaN / GaN array structures in the gate-drain drift region to reshape conventional AlGaN / GaN devices and obtain better microwave power characteristics. This embodiment adds an N+Polysi / AlGaN / GaN and N+Ge / AlGaN / GaN stacked structure, forming two current paths, significantly reducing gate-source resistance, improving the efficiency of GaN RF devices, reducing knee voltage, and increasing output power. The N+Polysi / AlGaN / GaN structure in this embodiment... The N+Ge / AlGaN / GaN stacked structure introduces an electric field along the vertical direction between N+Polysi or N+ and AlGaN / GaN, weakening the two-dimensional electric field distribution between the gate and drain. This improves the device's breakdown characteristics, reduces the gate-drain spacing Lgd and on-resistance Rds, and enhances the device's RF performance. Finally, the array-type N+Polysi / AlGaN / GaN and N+Ge / AlGaN / GaN stacked structures in this embodiment can improve the electric field distribution along the gate width, reducing the gate-drain spacing Lgd and on-resistance Rd, and making the Miller capacitance Cgd more uniform, thus improving the high linearity and power performance of the RF device.

[0049] The above embodiments are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

Claims

1. A method for fabricating a high-linearity radio frequency AlGaN / GaN device, characterized in that, Includes the following steps: Step 1: Select AlGaN, GaN, and SiC as substrate materials, and deposit SiN thin films on the substrate materials using chemical vapor deposition to obtain sample A; Step 2: Using photolithography, interconnect contact holes are exposed on sample A, and then SiN and AlGaN barrier layers are etched respectively, and the interconnect contact holes are opened in the drift region; Step 3: Form N-type polycrystalline silicon or N-type Ge on the aforementioned structure. The N-type polycrystalline silicon or N-type Ge is interconnected with the AlGaN / GaN two-dimensional electron gas through the interconnect contact holes. The N-type polycrystalline silicon is grown by low-pressure chemical vapor deposition and phosphorus atom implantation is performed. The polycrystalline silicon film is then N-doped and annealed. The N-type Ge film is formed by molecular beam epitaxy. Step 4: Using photolithography, a stacked array pattern is exposed in the gate-drain region on the interconnect contact hole. Then, reactive ion etching is used to etch the exposed N-type polysilicon or N-type Ge and the underlying SiN masking layer to obtain a stacked array structure spaced apart along the gate width direction. The stacked array structure is N-type polysilicon / AlGaN / GaN or N-type Ge / AlGaN / GaN, which is in contact with the drain region to obtain sample B. Step 5: Photolithography is performed on the sample B to expose the source and drain patterns of the ohmic contacts. Ti, Al, Ni and Au are evaporated with an electron beam. After resist removal and rapid thermal annealing, the source and drain ohmic contacts of the device are formed to obtain sample C. Step 6: Photolithography is performed on the sample C to expose the pattern of the Schottky gate. Ni and Au are evaporated with an electron beam. After resist removal and peeling, the Schottky gate is obtained, and finally an RF AlGaN / GaN device with a dual-channel stacked structure of gate and drain regions is fabricated.

2. The method for fabricating a high-linearity radio frequency AlGaN / GaN device according to claim 1, characterized in that: in, In step 1, the AlGaN / GaN is located above the SiC. The thickness of the SiN thin film is 90~110nm.

3. The method for fabricating a high-linearity radio frequency AlGaN / GaN device according to claim 1, characterized in that: in, In step 3, the thickness of the polycrystalline silicon thin film or the Ge thin film is 0.05~0.5um.

4. The method for fabricating a high-linearity radio frequency AlGaN / GaN device according to claim 1, characterized in that: in, In step 3, the sheet resistance is controlled at 50~120Ω / □ during the N-type doping process.

5. The method for fabricating a high-linearity radio frequency AlGaN / GaN device according to claim 1, characterized in that: in, In step 3, the N-type polycrystalline silicon or N-type Ge is positively charged, and the upper and lower surfaces of AlGaN are negatively charged and positively charged, respectively.

6. The method for fabricating a high-linearity radio frequency AlGaN / GaN device according to claim 1, characterized in that: in, In step 5, the rapid thermal annealing temperature is 840~860℃ and the time is 50~70s.

7. The method for fabricating a high-linearity radio frequency AlGaN / GaN device according to claim 1, characterized in that: in, In step 6, the dual-channel stacked structure is an N-type polysilicon / AlGaN / GaN or an N-type Ge / AlGaN / GaN dual-channel stacked structure.

8. A high-linearity radio frequency AlGaN / GaN device, characterized in that, include: The substrate material is made of AlGaN / GaN on SiC; N-type polysilicon or N-type Ge is disposed above the substrate material to form a stacked array structure spaced apart along the gate width direction. The stacked array structure is N-type polysilicon / AlGaN / GaN or N-type Ge / AlGaN / GaN, and it is in contact with the drain region. The N-type polycrystalline silicon or N-type Ge is interconnected with the AlGaN / GaN two-dimensional electron gas through the interconnect contact holes; The source electrode is disposed above the substrate material. The high linearity radio frequency AlGaN / GaN device is prepared by the method described in any one of claims 1 to 7.

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