Radio frequency GaN-based HEMT device with improved linearity and preparation method thereof

Abstract

The invention discloses a radio frequency GaN-based HEMT device with improved linearity and a preparation method thereof, the device sequentially comprises a substrate, a nucleating layer, a buffer layer, a channel layer and a barrier layer from bottom to top, and two-dimensional electron gas with high electron mobility is formed near the interface of the channel layer and the barrier layer. And removing the barrier layer and part of the channel layer in part of the region to form a groove, growing a III-nitride semiconductor material in the groove to form a heavily doped region and a lightly doped region which are connected, and enabling the lightly doped region to face the gate electrode. Ohmic contact is formed between the bottom of the source electrode and the upper surface of the heavily doped region, and a 2DEG-n--GaN-n +-GaN structure formed by two-dimensional electron gas below the gate electrode and the source electrode through the heavily doped region and the lightly doped region is equivalent to that a Schottky diode is inserted between the gate electrode and the source electrode. The transconductance flatness and the cut-off frequency flatness of the radio frequency GaN-based HEMT device are improved, and the dynamic input range, the input voltage swing and the output current swing of the device are widened, so that the linearity of the device is improved.

Description

Technical Field

[0001] The present invention relates to a radio frequency GaN-based HEMT device, in particular to a radio frequency GaN-based HEMT device with improved linearity and a preparation method thereof, belonging to the technical field of radio frequency GaN-based HEMT devices. Background Art

[0002] Gallium nitride (GaN) is a wide bandgap semiconductor material that has significant advantages in radio frequency (RF) and microwave power amplifier applications, mainly due to its wide bandwidth, high frequency response and high voltage resistance. Especially in high-frequency and high-power applications, GaN devices show better performance than traditional silicon devices. This makes GaN an ideal choice for RF power amplifiers in 4G LTE and 5G communication systems.

[0003] GaN HEMT (high electron mobility transistor) is a GaN-based heterostructure device, which usually forms a heterojunction with AlGaN (aluminum gallium nitride), thereby forming a two-dimensional electron gas (2DEG) between the two materials. This two-dimensional electron gas layer provides very high electron mobility and electron saturation velocity, which enables GaN HEMT to have higher current driving capability and power output capability. These characteristics make GaN HEMT a strong candidate to replace silicon-based power amplifiers, especially in applications that need to process high-frequency signals and high-power output, such as wireless communications, radar and satellite communications.

[0004] Although GaN HEMT excels in many aspects, it still faces an important challenge: nonlinear behavior. The nonlinear characteristics of GaN HEMT are particularly severe under high-frequency conditions. The nonlinear characteristics will cause distortion between the output signal and the input signal, which in turn affects the transmission efficiency and signal quality of the system. Especially at high-power output, the nonlinearity will be more prominent, which may cause signal distortion and affect the performance of the communication system. The nonlinearity in GaN HEMT is mainly caused by parasitic effects inside the device. Specifically, these parasitic effects include source-drain resistance (RS) and drain-source resistance (RD), which are usually closely related to factors such as the internal resistance, contact resistance and channel resistance of the device. By optimizing the design and material quality, these effects can be effectively mitigated and the performance and efficiency of GaN HEMT devices in high-frequency and high-power applications can be improved. For this reason, a RF GaN-based HEMT device with improved linearity and a preparation method thereof are designed to solve the above problems. Summary of the invention

[0005] The main purpose of the present invention is to provide a radio frequency GaN-based HEMT device with improved linearity and a preparation method thereof, which solves the problems of narrow transconductance swing and poor linearity of existing GaN-based HENT devices.

[0006] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0007] A radio frequency GaN-based HEMT device with improved linearity has a Schottky diode inserted between a gate electrode and a source electrode, thereby improving the transconductance flatness and cutoff frequency flatness of the radio frequency GaN-based HEMT device, broadening the dynamic input range, input voltage swing and output current swing of the radio frequency GaN-based HEMT device, and thus improving the linearity of the radio frequency GaN-based HEMT device.

[0008] In order to solve the problems existing in the prior art, the present invention provides a radio frequency GaN-based HEMT device with improved linearity and a preparation method thereof. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0009] An embodiment of the present invention provides a radio frequency GaN-based HEMT device structure with improved linearity, which includes a substrate, a nucleation layer, a buffer layer, a channel layer and a barrier layer from bottom to top, wherein the buffer layer, the channel layer and the barrier layer are group III nitride materials, and the group III nitride semiconductor is a combination of any two or more of GaN, AlN and InN.

[0010] A two-dimensional electron gas (2DEG) is formed between the channel layer and the barrier layer, serving as a conductive channel of the HEMT device.

[0011] A gate electrode is provided on the barrier layer, a drain electrode is provided on one side of the gate electrode, and the barrier layer and a portion of the channel layer are removed from a portion of the other side to form a groove, in which a group III nitride semiconductor material is grown to form a connected heavily doped region and a lightly doped region, wherein the heavily doped region is an N-type heavily doped n + , the lightly doped region is N-type lightly doped n - The lightly doped region faces the gate electrode.

[0012] The source electrode is set on the side of the gate electrode opposite to the drain electrode. The bottom of the source electrode forms an ohmic contact with the upper surface of the heavily doped region, and the source electrode does not directly contact the two-dimensional electron gas. The two-dimensional electron gas under the gate electrode and the source electrode form a 2DEG-n--GaN-n through the heavily doped region and the lightly doped region. + -GaN structure, which is equivalent to inserting a Schottky diode between the gate electrode and the source electrode, improves the linearity of RF GaN-based HEMT devices.

[0013] In one embodiment of the present invention, the drain electrode directly forms an ohmic contact with the two-dimensional electron gas of the channel layer, or forms a Schottky contact with the two-dimensional electron gas of the channel layer; the gate electrode forms a Schottky contact with the barrier layer, or forms a metal-insulator-semiconductor (MIS) structure with the barrier layer through a layer of insulating medium under the gate electrode.

[0014] In one embodiment of the present invention, a first passivation layer is formed above the barrier layer between the drain electrode and the gate electrode, and a second passivation layer is formed above the group III nitride material between the source electrode and the gate electrode. The material of the first passivation layer and the second passivation layer is one or a combination of SiN, SiO2, and Al2O3.

[0015] In one embodiment of the present invention, the materials of the heavily doped region and the lightly doped region are GaN, InGaN, or AlGaN, and the doping type is N-type, wherein the doping concentration of the heavily doped region is 1×10 18 -1×10 21 cm -3 , the doping concentration of the lightly doped region is 1×10 16 -1×10 18 cm -3 , the depth of the groove is 30-200nm.

[0016] In one embodiment of the present invention, the substrate is made of one of silicon, silicon carbide, sapphire and diamond.

[0017] In one embodiment of the present invention, the material of the nucleation layer is AlN, with a thickness of 50 nm-300 nm. The nucleation layer is used to release the lattice mismatch stress and thermal stress between the buffer layer and the substrate.

[0018] In one embodiment of the present invention, the material of the buffer layer is undoped GaN or AlGaN, and the thickness is 200 nm to 5 μm.

[0019] In one embodiment of the present invention, the material of the channel layer is GaN, InGaN or AlGaN, and the thickness is 50nm to 500nm.

[0020] In one embodiment of the present invention, the barrier layer is made of AlGaN, InGaN or AlN, and has a thickness of 5 nm to 50 nm.

[0021] In one embodiment of the present invention, the material of the drain electrode is any one or more combinations of Ti / Al / Ni, Mo, Pt, and Nb / Au.

[0022] In one embodiment of the present invention, the material of the gate electrode and the source electrode is any one of Ni / Au, Ti / Au, TiN / Au or Ta / Au.

[0023] In one embodiment of the present invention, the material of the first passivation layer and the second passivation layer is any one of Si3N4, SiO2, and Al2O3, and the thickness is 10 to 200 nm.

[0024] The present invention also provides a method for preparing a radio frequency GaN-based HEMT device with improved linearity, which is characterized by comprising the following steps:

[0025] Step 1: Cleaning the surface of the substrate;

[0026] Step 2: sequentially growing a nucleation layer, a buffer layer, a channel layer and a barrier layer on the substrate;

[0027] Step 3: Clean the epitaxial wafer and isolate the device;

[0028] Step 4: etching a portion of the barrier layer and the channel layer to form a groove, and growing a group III nitride material in the groove;

[0029] Step 5: Ion implantation of the group III nitride material in the groove and high temperature activation are performed to form a heavily doped region and a lightly doped region;

[0030] Step 6: growing a drain electrode on the barrier layer and performing annealing to form an ohmic contact;

[0031] Step 7: depositing a source electrode on the heavily doped region to form an ohmic contact;

[0032] Step 8: Depositing the gate electrode;

[0033] Step 9: Deposit a first passivation layer and a second passivation layer.

[0034] In one embodiment of the present invention, step 4 is to perform etching on a portion of the barrier layer and the channel layer to form a groove, and grow a lightly doped group III nitride material in the groove;

[0035] In one embodiment of the present invention, step 5 is to perform ion implantation and high-temperature activation in a partial area of ​​the group III nitride material on the side of the groove away from the gate electrode to form a heavily doped area, and the remaining lightly doped group III nitride material in the groove forms a lightly doped area.

[0036] Beneficial technical effects of the present invention:

[0037] The present invention provides a radio frequency GaN-based HEMT device with improved linearity and a preparation method thereof. The structure enables the device to exhibit wide transconductance and high linearity characteristics, solves the problem of relatively narrow transconductance swing of conventional GaN-based HEMT devices, stabilizes the gate's control ability over channel current, and enables the GaN-based HEMT device to have higher linearity, which is of great value to high-linear radio frequency devices. In addition, the processing technology of the material of the present invention is compatible with existing mature technologies, has low cost, is easy to promote, and has high feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic structural diagram of a radio frequency GaN-based HEMT device with improved linearity according to the present invention;

[0039] Figure 2 It is a schematic flow chart of a method for preparing a radio frequency GaN-based HEMT device with improved linearity according to Embodiment 2 of the present invention;

[0040] Figure 3 It is a schematic diagram of the process of a method for preparing a radio frequency GaN-based HEMT device with improved linearity according to Example 3 of the present invention.

[0041] In the figure: 1. substrate; 2. nucleation layer; 3. buffer layer; 4. channel layer; 5. barrier layer; 6. drain electrode; 7. gate electrode; 8. source electrode; 9. heavily doped region; 10. lightly doped region; 11. first passivation layer; 12. second passivation layer; 81. groove. DETAILED DESCRIPTION

[0042] In order to make the technical solution of the present invention more clear and specific to those skilled in the art, the present invention is further described in detail below in conjunction with embodiments and drawings, but the implementation manner of the present invention is not limited thereto.

[0043] Example 1

[0044] The transconductance obtained when the series resistance RS and RD are ignored is the intrinsic transconductance gm*. The saturation region transconductance of the HEMT device is

[0045]

[0046] When the series resistances RS and RD are not ignored, IDS generates a voltage drop across the source-drain series resistances RS and RD, which are derived from the channel resistance of the gate-free channel region between the gate-source and the gate-drain and the source-drain ohmic contact resistance RC.

[0047] The source resistance RS reduces the effective gate voltage between the gate and the source, which will affect the saturation region transconductance gm. The drain resistance RD increases the source-drain voltage VDsat when the current begins to saturate. However, when VDS>VDsat, VDS has no effect on the output current, so RD has no effect on gm.

[0048] Two adjacent grooves are successively arranged directly below the source electrode and in the middle area between the source electrode and the gate electrode. The bottom ends of the grooves are both located in the middle and upper part of the channel layer. GaN materials are grown in the grooves. By ion implantation, heavily doped n+ GaN materials are formed in the groove directly below the source electrode, and lightly doped n- GaN materials are formed in the groove in the middle area between the source electrode and the gate electrode. The two-dimensional electron gas concentration is high, which is considered to be n + Doping, where n - The groove has a low doping concentration, forming a high-resistance region.

[0049] In this way, the two-dimensional electron gas under the gate electrode and the source electrode form a Schottky diode structure through two doped grooves.

[0050] This structure enables the device to exhibit wide transconductance and high linearity characteristics, solving the problem of relatively narrow gm of conventional GaN-based HEMT devices, making them have flat gm, thereby stabilizing the gate's control ability over the channel current, making GaN-based HEMT devices have higher linearity, and having great value for high-linearity RF devices.

[0051] The present invention provides a high linearity GaN-based HEMT device, such as Figure 1 As shown, the device includes a substrate 1, a nucleation layer 2, a buffer layer 3, a channel layer 4 and a barrier layer 5 from bottom to top, wherein the buffer layer 3, the channel layer 4 and the barrier layer 5 are group III nitride materials, and the group III nitride semiconductor is a combination of any two or more of GaN, AlN and InN. A two-dimensional electron gas (2DEG) is formed between the channel layer 4 and the barrier layer 5, which serves as a conductive channel of the HEMT device. A gate electrode 7 is provided above the barrier layer 5, a drain electrode 6 is provided on one side of the gate electrode 7, and the barrier layer 5 and part of the channel layer 4 are removed from a part of the other side to form a groove 81, and a group III nitride semiconductor material is grown in the groove 81 to form a connected heavily doped region 9 and a lightly doped region 10, wherein the heavily doped region 9 is N-type heavily doped n+, and the lightly doped region 10 is N-type lightly doped n-. The lightly doped region 10 faces the gate electrode. A source electrode 8 is provided on the side of the gate electrode 7 opposite to the drain electrode 6. The bottom of the source electrode 8 forms an ohmic contact with the upper surface of the heavily doped region 9, and the source electrode 8 does not directly contact the two-dimensional electron gas. The two-dimensional electron gas below the gate electrode 7 and the source electrode 8 form a 2DEG-n--GaN-n through the heavily doped region 9 and the lightly doped region 10. + -GaN structure, which is equivalent to inserting a Schottky diode between the gate electrode 7 and the source electrode 8, improves the linearity of the RF GaN-based HEMT device.

[0052] Specifically, the drain electrode 6 directly forms an ohmic contact with the two-dimensional electron gas of the channel layer 4;

[0053] Specifically, the gate electrode 7 forms a Schottky contact with the barrier layer 5;

[0054] Specifically, a first passivation layer 11 is formed above the barrier layer 5 between the drain electrode 6 and the gate electrode 7 ; and a second passivation layer 12 is formed above the group III nitride material between the source electrode 8 and the gate electrode 7 .

[0055] The material of the first passivation layer (11) and the second passivation layer (12) is SiN.

[0056] Specifically, the materials of the heavily doped region 9 and the lightly doped region 10 are GaN, InGaN, or AlGaN, and the doping type is N-type, wherein the doping concentration of the heavily doped region 9 is 1×10 18 -1×10 21 cm -3 , the doping concentration of the lightly doped region 10 is 1×10 16 -1×10 18 cm -3 The depth of the groove 81 is 30-200 nm.

[0057] Preferably, the material of the heavily doped region 9 and the lightly doped region 10 is GaN, and the doping type is N-type, wherein the doping concentration of the heavily doped region 9 is 1×10 20 cm -3 , the doping concentration of the lightly doped region 10 is 5×10 173 .

[0058] Specifically, the depth of the groove 81 is 30-200 nm.

[0059] Preferably, the depth of the groove 81 is 80 nm.

[0060] Specifically, the substrate 1 is made of one of silicon, silicon carbide, sapphire and diamond.

[0061] Preferably, the substrate 1 is made of silicon carbide.

[0062] Specifically, the material of the nucleation layer 2 is AlN, and the thickness is 50 nm-300 nm. The nucleation layer 2 is used to release the lattice mismatch stress and thermal stress between the buffer layer 3 and the substrate.

[0063] Specifically, in one embodiment of the present invention, the material of the buffer layer 3 is undoped GaN or AlGaN, and the thickness is 200 nm to 5 μm.

[0064] Specifically, the material of the channel layer 4 is GaN, InGaN or AlGaN, and the thickness is 50 nm to 500 nm.

[0065] Specifically, the material of the barrier layer 5 is AlGaN, InGaN or AlN, and the thickness is 5 nm to 50 nm.

[0066] Specifically, the material of the drain electrode 6 is any one or more combinations of Ti / Al / Ni, Mo, Pt, and Nb / Au.

[0067] Specifically, the material of the gate electrode 7 and the source electrode 8 is any one of Ni / Au, Ti / Au, TiN / Au or Ta / Au.

[0068] Specifically, the material of the first passivation layer 11 and the second passivation layer 12 is any one of Si3N4, SiO2, and Al2O3, and the thickness is 10 to 200 nm.

[0069] Example 2

[0070] The present invention provides a method for preparing a high-linearity GaN-based HEMT device, such as Figure 2 As shown, the specific implementation steps are as follows:

[0071] Step 1: cleaning the surface of substrate 1;

[0072] Step 2: growing a nucleation layer 2, a buffer layer 3, a channel layer 4 and a barrier layer 5 in sequence on the substrate;

[0073] Step 3: Clean the epitaxial wafer and isolate the device;

[0074] Step 4: etching a portion of the barrier layer 5 and the channel layer 4 to form a groove 81, and growing a group III nitride material in the groove 81;

[0075] Step 5: ion implantation of the group III nitride material in the groove 81 and high temperature activation to form a heavily doped region 9 and a lightly doped region 10;

[0076] Step 6: growing a drain electrode 6 on the barrier layer 5 and performing annealing to form an ohmic contact;

[0077] Step 7: depositing a source electrode 8 on the heavily doped region 9 to form an ohmic contact;

[0078] Step 8: depositing a gate electrode 7;

[0079] Step 9: depositing a first passivation layer 11 and a second passivation layer 12 .

[0080] Example 3

[0081] A method for preparing a high linearity GaN-based HEMT device, such as Figure 3 As shown, the specific implementation steps are as follows:

[0082] Step 1: Cleaning the surface of the selected SiC substrate 1 with a thickness of 500 μm;

[0083] At 1000°C, hydrogen is introduced into the reaction chamber to remove pollutants on the surface of the substrate 1 and form a microscopic step structure on the surface of the substrate 1, thereby preparing for the subsequent epitaxial growth process of various epitaxial layers;

[0084] Step 2: using metal organic chemical vapor deposition to sequentially grow a nucleation layer 2, a buffer layer 3, a channel layer 4 and a barrier layer 5 on the substrate 1;

[0085] The nucleation layer 2 is made of AlN with a thickness of 100 nm, the buffer layer 3 is made of GaN with a thickness of 1.2 μm, and the channel layer 4 is made of GaN with a thickness of 300 nm;

[0086] A barrier layer 5 is grown on the channel layer 4 by metal organic chemical vapor deposition;

[0087] The barrier layer 5 is made of AlGaN with a thickness of 20 nm and an Al composition of 0.3;

[0088] Step 3: Clean the epitaxial wafer and isolate the device;

[0089] The work of cleaning epitaxial wafers mainly includes cleaning of organic matter, cleaning of inorganic matter and removal of surface passivation layer. Use acetone solution to ultrasonically clean the sample for 2 minutes, then put the sample into ethanol solution for ultrasonication for 3 minutes to remove the residual acetone liquid on the sample surface. Soak the sample in diluted HF solution for 1 minute to remove surface oxides and inorganic pollutants, and finally rinse with running deionized water and blow dry with a nitrogen gun. Removal of residual photoresist during the photolithography process and cleaning of the sample surface before metal evaporation are also required;

[0090] The mesa isolation adopts the mesa isolation technology which is less complex, less costly and easier to implement. The etching gas is Cl2 and the etching depth is 400nm.

[0091] Step 4: etching the barrier layer 5 and part of the channel layer 4; etching a groove 81, growing gallium nitride material in the groove 81, and then doping the left and right regions of the groove 81 by ion implantation;

[0092] Specifically, the barrier layer 5 region between the source electrode and the gate electrode is etched by reactive ion etching (RIE) to form a groove with a thickness of 100 nm.

[0093] Specifically, a low-damage Cl2 / BCl3 etching process is used, the etching equipment is reactive ion etching (RIE: Reactive Ion Etching), the etching rate is 2.5nm / min, and the etching depth is 100nm;

[0094] Specifically, by ion implantation, the heavily doped region 9 is heavily doped with n+ region, the doping concentration is 1×10 18 -1×10 21 cm -3 ; Make the lightly doped region 10 lightly doped n - region, the doping concentration is 1×10 13 -1×10 16 cm -3 ;

[0095] Step 5: growing a drain electrode 6 on the barrier layer 5 and performing annealing to form an ohmic contact;

[0096] Specifically, four metal layers were grown in the region by electron beam evaporation, using Ti / Al / Ni / Au, with corresponding film thicknesses of 22nm / 150nm / 55nm / 45nm, and then rapidly annealed in N2 at 880°C for 30s to alloy and form ohmic contacts;

[0097] Step 6: Deposit the source electrode 8 directly above the heavily doped n+ region 9 on the left side of the groove and perform annealing to make the source electrode and the heavily doped n+ region 9 on the left side of the groove + Region 9 forms an ohmic contact;

[0098] Specifically, the source electrode 8 is made, and a metal with a higher work function is selected as the source metal. In this embodiment, Ni / Cr laminated metal is used, and rapid annealing is performed under N2 at 880° C. for 30 seconds, so that the source electrode 8 and the n+ buried layer 9 form an ohmic contact;

[0099] Step 7: depositing a gate electrode 7;

[0100] Specifically, the gate electrode 7 usually uses a metal with a higher work function as the gate metal. In this embodiment, Ni / Au laminated metal is used. Ni / Au (50 / 150nm) double-layer metal is deposited using electron beam evaporation equipment. After the metal is evaporated, the sample is placed in a N2 atmosphere at 450°C for rapid annealing for 5 minutes to form a gate Schottky contact;

[0101] Step 8: preparing a first passivation layer 11 and a second passivation layer 12;

[0102] Specifically, a Si3N4 film with a thickness of 150 nm is deposited on the surface of the barrier layer by plasma enhanced chemical vapor deposition (PECVD).

[0103] The above description is only a further embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the scope disclosed by the present invention, which belong to the protection scope of the present invention.

Claims

1. A radio frequency GaN-based HEMT device with improved linearity, characterized in that: The invention comprises, from bottom to top, a substrate (1), a nucleation layer (2), a buffer layer (3), a channel layer (4) and a barrier layer (5); The buffer layer (3), the channel layer (4) and the barrier layer (5) are made of group III nitride materials. The group III nitride semiconductor is a combination of any two or more of GaN, AlN and InN. A two-dimensional electron gas (2DEG) is formed between the channel layer (4) and the barrier layer (5) as a conductive channel of the HEMT device. A gate electrode (7) is provided above the barrier layer (5). A drain electrode (6) is provided on one side of the gate electrode (7). The barrier layer (5) and part of the channel layer (4) are removed from a part of the other side to form a groove (81). A group III nitride semiconductor material is grown in the groove (81) to form a connected heavily doped region (9) and a lightly doped region (10), wherein the heavily doped region (9) is an N-type heavily doped n+ region and the lightly doped region (10) is an N-type lightly doped n+ region. - , the lightly doped region (10) faces the gate electrode, a source electrode (8) is arranged on the side of the gate electrode (7) opposite to the drain electrode (6), the bottom of the source electrode (8) forms an ohmic contact with the upper surface of the heavily doped region (9), the source electrode (8) is not in direct contact with the two-dimensional electron gas, and the two-dimensional electron gas below the gate electrode (7) and the source electrode (8) form a 2DEG-n--GaN-n+-GaN structure through the heavily doped region (9) and the lightly doped region (10), which is equivalent to inserting a Schottky diode between the gate electrode (7) and the source electrode (8).

2. The RF GaN-based HEMT device with improved linearity according to claim 1, characterized in that: The drain electrode (6) directly forms an ohmic contact with the two-dimensional electron gas of the channel layer (4), or forms a Schottky contact with the two-dimensional electron gas of the channel layer (4); The gate electrode (7) forms a Schottky contact with the barrier layer (5) or forms a metal-insulator-semiconductor (MIS) structure with the barrier layer (5) through a layer of insulating medium under the gate electrode (7).

3. According to the RF GaN-based HEMT device with improved linearity as claimed in claim 1, a first passivation layer (11) is provided above the barrier layer (5) between the drain electrode (6) and the gate electrode (7); A second passivation layer (12) is located above the group III nitride material between the source electrode (8) and the gate electrode (7); the materials of the first passivation layer (11) and the second passivation layer (12) are one or a combination of SiN, SiO2, and Al2O3.

4. According to the RF GaN-based HEMT device with improved linearity as claimed in claim 1, the material of the heavily doped region (9) and the lightly doped region (10) is GaN, or InGaN, or AlGaN, and the doping type is N-type, wherein the doping concentration of the heavily doped region (9) is 1×10 18 -1×10 21 cm -3 , the doping concentration of the lightly doped region (10) is 1×10 16 -1×10 18 cm -3 ; The depth of the groove (81) is 30-200 nm.

5. The RF GaN-based HEMT device with improved linearity according to claim 1, characterized in that: The substrate (1) is made of one of silicon, silicon carbide, sapphire and diamond.

6. The RF GaN-based HEMT device with improved linearity according to claim 1, characterized in that: The material of the nucleation layer (2) is AlN, and the thickness is 50nm-300nm. The nucleation layer (2) is used to release the lattice mismatch stress and thermal stress between the buffer layer (3) and the substrate. The material of the buffer layer (3) is undoped GaN or AlGaN, and the thickness is 200nm to 5μm; The material of the channel layer (4) is GaN, InGaN or AlGaN, and the thickness is 50nm to 500nm; The barrier layer (5) is made of AlGaN, InGaN or AlN, and has a thickness of 5nm to 50nm.

7. The RF GaN-based HEMT device with improved linearity according to claim 1, characterized in that: The material of the drain electrode (6) is any one or more combinations of Ti / Al / Ni, Mo, Pt, and Nb / Au; The material of the gate electrode (7) and the source electrode (8) is any one of Ni / Au, Ti / Au, TiN / Au or Ta / Au; The material of the first passivation layer (11) and the second passivation layer (12) is any one of Si3N4, SiO2, and Al2O3, and the thickness is 10 to 200 nm.

8. A method for preparing a radio frequency GaN-based HEMT device with improved linearity, based on the radio frequency GaN-based HEMT device with improved linearity according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: cleaning the surface of the substrate (1); Step 2: sequentially growing a nucleation layer (2), a buffer layer (3), a channel layer (4) and a barrier layer (5) on a substrate; Step 3: Clean the epitaxial wafer and isolate the device; Step 4: etching a portion of the barrier layer (5) and the channel layer (4) to form a groove (81), and growing a group III nitride material in the groove (81); Step 5: performing ion implantation and high temperature activation of the group III nitride material in the groove (81) to form a heavily doped region (9) and a lightly doped region (10); Step 6: growing a drain electrode (6) on the barrier layer (5) and performing annealing to form an ohmic contact; Step 7: depositing a source electrode (8) on the heavily doped region (9) to form an ohmic contact; Step 8: depositing a gate electrode (7); Step 9: Depositing a first passivation layer (11) and a second passivation layer (12).

9. The method for preparing a radio frequency GaN-based HEMT device with improved linearity and a method for preparing the same according to claim 8, characterized in that: Step 4: etching a portion of the barrier layer (5) and the channel layer (4) to form a groove (81), and growing a lightly doped group III nitride material in the groove (81); Step 5: ion implantation and high-temperature activation are performed in a partial area of ​​the group III nitride material on a side of the groove (81) away from the gate electrode to form a heavily doped area (9), and the remaining lightly doped group III nitride material in the groove (81) forms a lightly doped area (10); The other steps are the same as those in claim 8.

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