A high-heat-dissipation GaN nanowire radio frequency device and a preparation method thereof

Abstract

The application belongs to the technical field of semiconductor devices, and particularly relates to a high-heat-dissipation GaN nanowire radio frequency device and a preparation method thereof. The radio frequency device comprises a heterojunction bonding substrate, a bonding intermediate layer, an AlGaN / GaN nanowire (a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer, a GaN cap layer), a passivation layer and an electrode layer. The electrode layer comprises a source electrode, a gate electrode and a drain electrode. The passivation layer is prepared by front deposition and covers the nanowires and the gaps between the nanowires, so that the preparation of the high-heat-dissipation nanowire transistor is realized, and the linearity reduction of the device caused by the self-heating effect is solved. The gate is opened, the thickness of the passivation layer on each nanowire is controlled, the equal-difference distribution is realized, the linearity of the device is improved by using the transconductance compensation effect, the gate voltage swing of the radio frequency device can be effectively improved, and the usable range of the device is greatly enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor devices, and in particular relates to a high-heat dissipation GaN nanowire radio frequency device and a preparation method thereof. Background Art

[0002] GaN is a preferred RF material due to its inherent high-frequency characteristics. HEMT devices, constructed from AlGaN / GaN heterostructures, are particularly well-represented as RF devices due to their ability to achieve high carrier concentration and high mobility without doping. However, issues such as parasitic capacitance, nonlinear transconductance, and trap defects often hinder GaN devices from fully realizing their material advantages in the RF field. Nonlinear transconductance is a major factor affecting device nonlinearity. During rapid switching, GaN devices are affected by polar optical phonon scattering and interface roughness scattering, which limits carrier mobility. Furthermore, during rapid switching, self-heating increases channel resistance, reducing transconductance. This, combined with surface defects, limits the RF performance of HEMT devices. Summary of the Invention

[0003] To address the above-mentioned issues, the present invention provides a high-heat dissipation GaN nanowire radio frequency device and a method for preparing the same. The method uses dry etching, laser lift-off, and heterojunction bonding to achieve nanowire epitaxial fabrication, and further fabricates nanowire transistors through photolithography. The nanowires can further reduce carrier scattering, compensating for the restriction of carrier mobility of current HEMT devices due to scattering. At the same time, a boron nitride (BN) passivation layer with excellent heat dissipation performance is deposited between the nanowires for sidewall protection and heat dissipation filling. The high heat dissipation coefficient further addresses the self-heating effect of the channel, preventing the heat generated by the channel from increasing the resistance and limiting the device's radio frequency performance. Furthermore, the present invention provides a transconductance compensation method and a method for increasing the linear amplification area. By controlling the thickness of the passivation layer above each nanochannel and gradually changing the passivation thickness, the threshold voltage of each nanowire device is effectively changed, achieving transconductance compensation, and improving the gate voltage swing of the entire device, so that the transconductance of the device remains constant over a larger gate voltage range, effectively increasing the device linearity.

[0004] To achieve the above-mentioned objectives, the present invention provides a high-heat dissipation GaN nanowire RF device, which includes a heterogeneous substrate and a SiO2 bonding layer, a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer, a GaN cap layer, a first passivation layer, an electrode layer and a second passivation layer arranged in sequence. The electrode layers are arranged in sequence as a source electrode, a gate electrode and a drain electrode. The GaN channel layer, the AlN insertion layer, the AlGaN barrier layer and the GaN cap layer constitute a nanowire array, which is prepared by an etching method.

[0005] Furthermore, the nanowire array is a group of 8-15 nanowires, and the GaN buffer layer is etched within a certain range outside the nanowire array to form a mesa isolation; a first passivation layer with a high heat dissipation coefficient and a low dielectric constant is deposited, and the passivation layer completely covers the upper surface and side edges of the nanowires.

[0006] Furthermore, the source electrode and the drain electrode are respectively deposited on the AlGaN barrier layer through the first passivation layer and the GaN cap layer by a passivation opening method, and the bottom of the gate electrode is connected to the upper surface of the first passivation layer; the source electrode is close to the gate electrode, and the drain electrode is far away from the gate electrode.

[0007] Furthermore, the second passivation layer is connected to the first passivation layer, completing the openings of the source electrode PAD, the gate electrode PAD, and the drain electrode PAD.

[0008] Furthermore, the foreign substrate includes any one of diamond, aluminum nitride or sapphire, and the first passivation layer and the second passivation layer are materials with high heat dissipation coefficient and low dielectric constant.

[0009] The present invention also provides a method for preparing a high-heat dissipation GaN nanowire radio frequency device, the method comprising the following steps:

[0010] (1) An AlN nucleation layer, a GaN high-resistance buffer layer, a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer, and a GaN cap layer are sequentially grown on a foreign substrate;

[0011] (2) Patterning of the nanowire array is achieved based on mask lithography, and the nanowire array is prepared by inductively coupled plasma etching to expose the GaN high-resistance buffer layer;

[0012] (3) Using temporary bonding glue and Si temporary substrate to complete temporary bonding of the nanowire array epitaxial wafer, and polishing the sapphire substrate;

[0013] (4) Laser stripping is used to remove the sapphire substrate, and then immersion in hydrochloric acid is used to remove the Ga atoms at the bottom.

[0014] (5) Chemical mechanical polishing is used to polish the surface of the nanowire array wafer with a temporary support substrate, and atomic layer deposition equipment is used to deposit SiO2 on the surface and the foreign substrate;

[0015] (6) Plasma surface activation bonding is used to complete the activation and bonding of the nanowire array wafer and the heterogeneous substrate, a laser debonding method is used to remove the temporary bonding substrate, and the bonding glue is removed by soaking in a debonding solution to obtain a heterogeneous substrate nanowire array wafer;

[0016] (7) Depositing the first passivation layer BN thin film on the top and side of the nanowire, photolithography holes for source and drain are opened, etching exposes the AlGaN barrier layer, electron beam evaporation deposits source and drain electrodes, and high temperature annealing realizes ohmic contact;

[0017] In this step, BN has excellent electrical insulation properties and a relatively low dielectric constant (3-4), making it suitable for use in high-frequency applications without generating excessive parasitic capacitance. Furthermore, its high heat dissipation coefficient of 60 W / m·K facilitates heat dissipation.

[0018] At the same time, by dividing the conventional AlGaN / GaN channel into multiple nanowire channels and using high thermal conductivity BN as a passivation layer, the concentration of heat sources in the HEMT channel is effectively alleviated, especially the heat source concentration problem on the side of the gate close to the drain. The continuous heat source is etched into separate channels and BN is deposited between the heat sources to effectively dissipate heat. At the same time, the distance between the channel and the substrate is shortened, and diamond (or AlN) with the highest thermal conductivity is used to greatly alleviate the channel self-heating effect, reducing the transconductance change problem caused by the increase in channel resistance due to the self-heating effect of the device under high-frequency switching, thereby improving linearity.

[0019] (8) Opening a gate window, depositing a gate electrode on the first passivation layer by electron beam evaporation; depositing a second passivation layer to protect the electrode;

[0020] This step uses ALD to deposit a dense, high-heat dissipation passivation layer (such as AlN) covering the first passivation layer and the upper surface of the electrode. This can be used to protect the electrode area and further improve the device's heat dissipation capability.

[0021] (9) Opening holes in the source, drain, and gate electrodes PAD and etching to expose the PAD metal surface, thereby obtaining the high heat dissipation GaN nanowire RF device.

[0022] Furthermore, after step (4), the method further includes exposing the GaN channel layer by inductively coupled plasma etching to further reduce the thickness of the buffer layer.

[0023] This step can reduce the distance of device channel heat dissipation and improve heat dissipation capacity.

[0024] The present invention also provides a method for transconductance compensation of a GaN nanowire radio frequency device, the method comprising the following steps:

[0025] (1) After the high heat dissipation GaN nanowire radio frequency device is prepared in step (7), photolithography is used to pattern photoresist in the gate region of each nanowire, and inductively coupled plasma etching is used to obtain GaN nanowire arrays with different passivation layer thicknesses;

[0026] (2) performing photolithography on the wafer with the first passivation layer again to deposit a gate electrode, wherein the gate electrode is deposited on the opening area with different thicknesses of the first passivation layer;

[0027] (3) Depositing a second passivation layer, opening the source, drain, gate, and PAD, and etching to expose the PAD metal surface, thereby achieving transconductance compensation of the GaN nanowire RF device.

[0028] The present invention also provides a high-linearity GaN nanowire RF device manufactured using the above-mentioned method of transconductance compensation GaN nanowire RF device. The high-linearity GaN nanowire RF device controls the thickness of the passivation layer above each nanochannel, gradually changes the passivation thickness gradient, changes the threshold voltage of each nanowire device, and thus increases the wire grain size of the GaN nanowire RF device.

[0029] The above method can improve the linearity of GaN RF devices. By bonding to a heterogeneous substrate and depositing a high thermal conductivity passivation layer before the nanowires, it can greatly solve the problem of heat accumulation in the GaN channel region. By adjusting the thickness of the passivation layer under the gate to achieve transconductance compensation, the power amplification capability of the GaN RF device is effectively increased, avoiding the complex and difficult integration problems of conventional GaN devices caused by setting up peripheral feedback circuits, and also avoiding the short channel effect caused by shortening the channel.

[0030] Compared with the prior art, the present invention has the following advantages and technical effects:

[0031] The present invention prepares nanowire transistors through photolithographic processing. The nanowires can further reduce carrier scattering, compensating for the restriction of carrier mobility of current HEMT devices due to scattering. At the same time, a boron nitride (BN) passivation layer with excellent heat dissipation performance is deposited between the nanowires for sidewall protection and heat dissipation filling. The high heat dissipation coefficient further solves the self-heating effect of the channel, avoiding the heat generated by the channel increasing the resistance and limiting the RF performance of the device. Furthermore, the present invention provides a transconductance compensation method and a method for increasing the linear amplification area. By controlling the thickness of the passivation layer above each nanochannel and gradually changing the passivation thickness, the threshold voltage of each nanowire device is effectively changed, achieving transconductance compensation, and improving the gate voltage swing of the entire device. The transconductance of the device remains constant within a larger gate voltage range, effectively improving the linearity of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 Schematic diagram of the overall structure of a GaN nanowire radio frequency device on a heterogeneous substrate according to an embodiment of the present invention;

[0034] Figure 2 Schematic diagram of the structure of a GaN radio frequency epitaxial wafer on a sapphire substrate according to an embodiment of the present invention;

[0035] Figure 3 Schematic diagram of the preparation of a nanochannel in an embodiment of the present invention, wherein the left figure is a main view and the right figure is a top view;

[0036] Figure 4 is a schematic diagram of temporary bonding in an embodiment of the present invention;

[0037] Figure 5 is a schematic diagram of a laser lift-off method according to an embodiment of the present invention;

[0038] Figure 6 This is a structural diagram of removing the sapphire substrate in an embodiment of the present invention;

[0039] Figure 7 is a schematic diagram of removing the GaN high-resistance buffer layer in an embodiment of the present invention;

[0040] Figure 8 Schematic diagram of depositing SiO2 on a heterogeneous substrate and a nanowire wafer in an embodiment of the present invention;

[0041] Figure 9 Schematic diagram of heterogeneous bonding in an embodiment of the present invention;

[0042] Figure 10 is a schematic diagram of the embodiment of the present invention after the temporary substrate is removed after heterogeneous bonding;

[0043] Figure 11 Schematic diagram of depositing the first passivation layer on a heterogeneously bonded GaN nano-RF wafer according to an embodiment of the present invention;

[0044] Figure 12 Schematic diagram of an open-source drain-gate window deposition electrode according to an embodiment of the present invention;

[0045] Figure 13 Schematic diagram of the structure of a high linearity device prepared in an embodiment of the present invention;

[0046] Figure 14 It is a structural schematic diagram of preparing a transconductance compensation high linearity device in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0048] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0049] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0050] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0051] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0052] The high-heat dissipation GaN nanowire radio frequency device prepared in the present invention includes a diamond heterogeneous substrate and a SiO2 bonding layer, a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer, a GaN cap layer, a passivation layer and an electrode layer and a second passivation layer in sequence, wherein the electrode layer is sequentially arranged as a source electrode, a gate electrode and a drain electrode; and the GaN channel layer, the AlN insertion layer, the AlGaN barrier layer and the GaN cap layer are prepared as a nanowire array by etching; the first passivation layer is located above the nanowires and between the nanowires; the above-mentioned passivation layer is usually made of a material with a low dielectric constant and excellent heat dissipation performance.

[0053] Specifically, the nanowire arrays mentioned above are usually grouped into groups of 8-15, and a GaN buffer layer is etched within a certain range outside the nanowire array to form a mesa isolation; a first passivation layer with a high heat dissipation coefficient and a low dielectric constant is deposited, and the first passivation layer completely covers the upper surface and side edges of the nanowires;

[0054] The source electrode and drain electrode are respectively deposited on the AlGaN barrier layer by passing through the first passivation layer and the GaN cap layer through a passivation opening method, and the bottom of the gate electrode is connected to the upper surface of the first passivation layer; the source electrode is close to the gate electrode, and the drain electrode is separated from the gate electrode;

[0055] The second passivation layer is connected to the first passivation layer, completing the openings of the source electrode PAD, the gate electrode PAD, and the drain electrode PAD.

[0056] Specifically, the nanowire array GaN radio frequency device further includes etching of a GaN high-resistance buffer layer and ALD deposition of a SiO2 bonding layer, and the heterogeneous substrate is located below the SiO2 bonding layer.

[0057] The overall structure diagram of the high heat dissipation GaN nanowire RF device prepared in the present invention is shown in Figure 1 In the above-mentioned nanowire array GaN radio frequency device, the nanowires are arrayed according to actual needs, and the activation characteristics of the SiO2 surface are increased by plasma activation bonding, and the heterogeneous bonding channel device is completed with a high heat dissipation heterogeneous substrate (such as diamond, aluminum nitride); the passivation layer with high heat dissipation coefficient and low dielectric constant (such as boron nitride) is formed above the nanochannel and between the nanowires. While separating the dense heat sources, the heat dissipation passivation layer is filled to effectively improve the heat dissipation, and the dielectric constant itself is small, and the parasitic capacitance under high-speed switching is small, which is very suitable for the use of radio frequency devices; the source and drain electrodes are opened through the first passivation layer, and the electrodes are deposited on the exposed AlGaN, and the ohmic contact electrodes are prepared by high-temperature annealing in a nitrogen atmosphere; the gate electrode is deposited on the first passivation layer to form an MIS structure, which further reduces gate leakage and improves device performance; the second passivation layer is covered on the first passivation layer and the electrode; the second passivation layer is etched to expose the electrode PAD surface.

[0058] The present invention will be further described in detail below with reference to specific examples and drawings, but the embodiments of the present invention are not limited thereto.

[0059] Example 1

[0060] Embodiment 1 of the present invention provides a method for preparing a GaN nanowire radio frequency device with high heat dissipation, comprising the following steps:

[0061] (1) On a sapphire substrate, a 40-50 nm AlN nucleation layer, a 1-3 μm GaN high-resistance buffer layer, a 100-200 nm GaN channel layer, a 1-3 nm AlN insertion layer, a 15-40 nm AlxGa1-xN barrier layer (x = 0.2-0.4) and a 1-3 nm GaN layer are sequentially grown to obtain an epitaxial wafer;

[0062] (2) Based on mask lithography, the nanowire array is patterned and an inductively coupled plasma (ICP) dry etching device is used to etch and prepare the HEMT nanowire array. The specific parameters are as follows: for the wafer after lithography, Cl2 / BCl3 (60 / 10 sccm) is used at a power of 200 W and a pressure of 8 Pa to etch to the GaN high-resistance buffer layer. The etching depth is (117 nm to 246 nm);

[0063] (3) Use a glue spreader to spin-coat a temporary bonding adhesive (laser debonding adhesive). The spin coating process is 500 rpm for 5 seconds and then 2000 rpm for 30 seconds. The thickness of the spin-coated adhesive is 0.9 to 1.1 μm. Heat it on a hot plate at 250 to 300 degrees Celsius for 5 to 10 minutes to complete the curing. Select a Si wafer or a sapphire substrate as the temporary substrate and bond it to the process wafer of the spin-coated bonding adhesive through a bonding device. The bonding parameters are 200°C and 500 to 1000N. Place the bonded process wafer on a polishing machine to complete the polishing of the sapphire substrate.

[0064] (4) Place the polished epitaxial wafer in a laser lift-off device with a laser wavelength of 248nm KrF excimer laser and a photon energy in the range of 3.50-5.00eV, which is lower than the band gap energy of sapphire 9.9eV but higher than 3.44eV of GaN, to ensure that the laser energy is absorbed by the GaN layer and the sapphire substrate is lifted off. After lift-off, the epitaxial wafer with the temporary substrate is placed in a solution of HCl:H2O (1:1) for 5-10 minutes to further remove the Ga element remaining on the back side due to the high-energy laser, and then rinsed with deionized water, dried, and finally dried using inductively coupled plasma (ICP). The etching equipment is used to etch and prepare the GaN buffer layer, further reducing the thickness, easing the distance of device channel heat dissipation, and improving the heat dissipation capability. The specific parameters are as follows: for the wafer after photolithography, Cl2 / BCl3 (60 / 10sccm) is used at a power of 200W and a pressure of 8Pa to etch the GaN high-resistance buffer layer to a depth of (1μm to 3μm), thereby obtaining a nanowire array of a temporary substrate, bonding adhesive and GaN cap layer, AlGaN barrier layer, AlN insertion layer, and GaN channel layer;

[0065] (5) Chemical polishing of the surface of the process wafer, i.e., the GaN channel layer, is performed using a CMP device to achieve global flatness, achieving a surface roughness of <0.5 nm. Atomic layer deposition (ALD) is then used to deposit SiO2 on the CMPed process wafer and the heterogeneous bonded substrate (diamond, AlN) to a thickness of 30-50 nm.

[0066] (6) Plasma surface activation bonding is used to complete the activation and bonding of the nanowire array wafer and the heterogeneous substrate to achieve wafer bonding. The specific parameters are as follows: oxygen plasma is introduced into a vacuum environment of 0.1-0.5 Pa to bombard the SiO2 surface with a power of 60-150 W. After the surface activation is completed, the robot arm is controlled to perform alignment bonding. The heterogeneous substrate bonding is achieved at a pressure of 2000-3500 N and a temperature of 200-300 degrees Celsius to obtain a wafer with a diamond substrate (or AlN) and SiO2 The process wafer consists of a bonding layer, a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer, a GaN cap layer, a bonding adhesive, and a temporary substrate. The temporary substrate is then peeled off using a laser debonding process to create a heterogeneous substrate nanowire process wafer. The specific process involves selecting a wavelength less than 355nm and requiring an instantaneous power density of 180-300mj / cm2 for laser irradiation and peeling. After debonding, the temporary substrate is removed and then immersed in a stripping solution to remove the bonding adhesive, resulting in a complete nanowire array process wafer with a heterogeneous substrate.

[0067] (7) Using atomic layer deposition equipment, introduce boron trifluoride (BF3) and ammonia (NH3), and deposit the first passivation layer BN film on the surface and side of the nanowire at 200-300°C and 10-100Pa. The deposition thickness is 200-300nm. After that, photolithography and ICP dry etching are used to passivate the source and drain electrodes, and Ti / Al / Ni / Au (20 / 120 / 30 / 60nm) is deposited by electron beam evaporation (EBL). The nanowire is placed in a high-temperature rapid annealing furnace, introduced into a 5-10slm nitrogen atmosphere, and rapidly heated to 850°C. Annealing is performed for 30-60s to achieve a contact resistance of less than 0.5Ω*mm. Photolithography and dry etching are used to reasonably thin the first passivation layer in the gate area to (10-20nm), and Ni / Au (30nm / 100nm) is deposited by electron beam evaporation to prepare an MIS structure gate electrode.

[0068] (8) A dense high-heat dissipation passivation layer (such as AlN) is deposited using ALD to cover the first passivation layer and the upper surface of the electrode, and holes are opened in the second passivation layer for the gate PAD, source PAD, and drain PAD to expose the electrode PAD, completing the preparation of the final device.

[0069] Among them, the specific flow chart of the high heat dissipation GaN nanowire RF device in the present invention is shown in Figure 2-Figure 12The presence of nanowires in the product produced by this invention transforms the planar two-dimensional electron gas channel into an array of one-dimensional nanowire channels, which are less susceptible to Coulomb scattering, improving the device's transconductance and linearity. Furthermore, a high-heat dissipation coefficient passivation layer is interspersed between the nanochannels, effectively alleviating the problem of concentrated heat sources in the planar two-dimensional electron gas channel, greatly reducing the self-heating effect and improving linearity. Furthermore, this invention further reduces the transmission distance between the carrier channel and the high-heat dissipation substrate, shortening the heat transfer path and improving heat dissipation, thereby effectively enhancing the device's RF amplification capability under high-speed switching conditions.

[0070] Example 2

[0071] Example 2 of the present invention provides a method for preparing a transconductance-compensated GaN nanowire radio frequency device. The initial steps of the preparation method are consistent with the preparation steps before step (8) of Example 1. The subsequent preparation steps are as follows:

[0072] When preparing the gate electrode, photolithography and ICP dry etching methods are used to achieve the equidistant thickness of the passivation layer under the gate. The passivation layer under the gate of a group of nanowire devices has equidistant thickness (such as 4 / 6 / 8 / 10 / 12 / 14 / 16 / 18nm). The threshold voltage of the device exhibits different gate control capabilities due to the different thicknesses of the gate passivation layer. Therefore, the threshold voltage of each nanochannel also exhibits a different turn-on voltage due to the different thicknesses of the dielectric layer under the gate, thereby obtaining nanowires with different transfer characteristic curves. Further, by achieving common source and common drain through a single deposition of the nanowire array, the overall transconductance compensation is achieved, resulting in a larger gate voltage swing and stable transconductance, thereby improving the linearity of the GaN RF device, and thus obtaining a transconductance-compensated GaN nanowire RF device. The structural schematic diagram of the transconductance-compensated high-linearity device prepared in this embodiment is shown in FIG. Figure 13-14 .

[0073] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A high heat dissipation GaN nanowire radio frequency device, characterized in that: include: A heterogeneous substrate and a SiO2 bonding layer, a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer, a GaN cap layer, a first passivation layer, an electrode layer and a second passivation layer sequentially arranged on the heterogeneous substrate, wherein the electrode layer is sequentially spaced apart with a source electrode, a gate electrode and a drain electrode, the GaN channel layer, the AlN insertion layer, the AlGaN barrier layer and the GaN cap layer constitute a nanowire array, which is prepared by an etching method, wherein the first passivation layer completely covers the upper surface and side edges of the nanowires, and the material of the first passivation layer is boron nitride; The thickness of the first passivation layer above each nanochannel is gradually changed, which changes the threshold voltage of each nanowire device and thus increases the wire grain size of the GaN nanowire radio frequency device.

2. The high heat dissipation GaN nanowire RF device according to claim 1, characterized in that: The nanowire array is a group of 8-15 nanowires, and etching is performed to the GaN buffer layer within a certain range outside the nanowire array to form a mesa isolation; Deposit a first passivation layer with high heat dissipation coefficient and low dielectric constant.

3. The high heat dissipation GaN nanowire RF device according to claim 1, characterized in that: The source electrode and the drain electrode are respectively deposited on the AlGaN barrier layer through the first passivation layer and the GaN cap layer by a passivation opening method, and the bottom of the gate electrode is connected to the upper surface of the first passivation layer; The source electrode is close to the gate electrode, and the drain electrode is far away from the gate electrode.

4. The high heat dissipation GaN nanowire RF device according to claim 1, characterized in that: The second passivation layer is connected to the first passivation layer, and the second passivation layer is provided with openings for the source electrode PAD, the gate electrode PAD, and the drain electrode PAD.

5. The high heat dissipation GaN nanowire RF device according to claim 1, characterized in that: The heterogeneous substrate includes any one of diamond, aluminum nitride or sapphire, and the second passivation layer is a material with high heat dissipation coefficient and low dielectric constant.

6. A method for preparing a high heat dissipation GaN nanowire radio frequency device according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: (1) An AlN nucleation layer, a GaN high-resistance buffer layer, a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer, and a GaN cap layer are sequentially grown on a foreign substrate; (2) Patterning of the nanowire array is achieved based on mask lithography, and the nanowire array is prepared by inductively coupled plasma etching to expose the GaN high-resistance buffer layer; (3) Using temporary bonding glue and Si temporary substrate to complete temporary bonding of the nanowire array epitaxial wafer, and polishing the sapphire substrate; (4) Laser stripping is used to remove the sapphire substrate, and then immersion in hydrochloric acid is used to remove the Ga atoms at the bottom. (5) Chemical mechanical polishing is used to polish the surface of the nanowire array wafer with a temporary support substrate, and atomic layer deposition equipment is used to deposit SiO2 on the surface and the foreign substrate; (6) Plasma surface activation bonding is used to complete the activation and bonding of the nanowire array wafer and the heterogeneous substrate, a laser debonding method is used to remove the temporary bonding substrate, and the bonding glue is removed by soaking in a debonding solution to obtain a heterogeneous substrate nanowire array wafer; (7) Depositing the first passivation layer BN thin film on the top and side of the nanowire, photolithography holes for source and drain are opened, etching exposes the AlGaN barrier layer, electron beam evaporation deposits source and drain electrodes, and high temperature annealing realizes ohmic contact; (8) patterning photoresist in the gate region of each nanowire using photolithography, and etching using inductively coupled plasma to obtain GaN nanowire arrays with different first passivation layer thicknesses; (9) performing photolithography on the wafer with the first passivation layer again to deposit a gate electrode, wherein the gate electrode is deposited on the opening area with different thicknesses of the first passivation layer; (10) depositing a second passivation layer, opening the source, drain, and gate PAD, and etching to expose the PAD metal surface to achieve transconductance compensation of the GaN nanowire RF device; (11) Opening a gate window, depositing a gate electrode on the first passivation layer by electron beam evaporation; depositing a second passivation layer to protect the electrode; (12) Opening holes in the source, drain, and gate electrodes PAD, and etching to expose the PAD metal surface, thereby obtaining the high heat dissipation GaN nanowire RF device.

7. The method for preparing a high heat dissipation GaN nanowire radio frequency device according to claim 6, wherein: After step (4), the method further includes exposing the GaN channel layer by inductively coupled plasma etching to further reduce the thickness of the buffer layer.

Images