阅读说明：本技术 GaN基HEMT器件及其制备方法 (GaN-based HEMT device and preparation method thereof ) 是由 王文博 程永健 李家辉 邹鹏辉 李哲 于 2021-11-15 设计创作，主要内容包括：本发明提供一种GaN基HEMT器件及其制备方法,在衬底上先形成外延结构及SiN钝化保护层,而后形成源极区及漏极区,及对应的源电极及漏电极,之后去除SiN钝化保护层,并进行表面清洗后,再采用原子层沉积及等离子退火工艺形成单晶AlN势垒层,以调制GaN沟道内二维电子气,同时在AlGaN势垒层内形成区域性薄层附属沟道,以提高器件整体线性度,且在同一沉积腔内采用原子层沉积在单晶AlN势垒层上形成非晶AlN钝化保护层,由于采用连续原位原子层沉积单晶和非晶AlN层,可以提高晶体/非晶AlN的界面质量,以优化器件Pulse-IV特性,且AlN层的高热导率,较好的散热性,还可以提高器件整体散热性能。(The invention provides a GaN-based HEMT device and a preparation method thereof, an epitaxial structure and a SiN passivation protective layer are firstly formed on a substrate, then forming a source region and a drain region, and a corresponding source electrode and a corresponding drain electrode, then removing the SiN passivation protective layer, after surface cleaning, adopting atomic layer deposition and plasma annealing process to form a monocrystal AlN barrier layer to modulate two-dimensional electron gas in the GaN channel, meanwhile, a regional thin auxiliary channel is formed in the AlGaN barrier layer to improve the overall linearity of the device, and an amorphous AlN passivation protective layer is formed on the single crystal AlN barrier layer by adopting atomic layer deposition in the same deposition cavity, because the single crystal and the amorphous AlN layer are deposited by adopting the continuous in-situ atomic layer, the interface quality of the crystal/amorphous AlN can be improved, the device Pulse-IV characteristic is optimized, the AlN layer has high heat conductivity and good heat dissipation performance, and the overall heat dissipation performance of the device can be improved.)

1. A preparation method of a GaN-based HEMT device is characterized by comprising the following steps:

providing a substrate;

forming an epitaxial structure on the substrate, wherein the epitaxial structure comprises a GaN layer and an AlGaN barrier layer which are overlapped from bottom to top;

forming an SiN passivation protective layer covering the AlGaN barrier layer on the AlGaN barrier layer;

forming source and drain regions in the epitaxial structure, the source and drain regions penetrating through the AlGaN barrier layer and extending bottom into the GaN layer;

patterning the SiN passivation protection layer to expose the source region and the drain region;

forming a source electrode in contact with the source region and a drain electrode in contact with the drain region;

removing the SiN passivation protective layer, exposing the AlGaN barrier layer, and cleaning the surface of the AlGaN barrier layer;

forming a single crystal AlN barrier layer on the exposed AlGaN barrier layer by adopting an atomic layer deposition and plasma annealing process, and forming an amorphous AlN passivation protection layer on the single crystal AlN barrier layer by adopting the atomic layer deposition in the same deposition cavity;

and patterning the single-crystal AlN barrier layer and the amorphous AlN passivation protection layer to expose the source electrode and the drain electrode.

2. The method for manufacturing a GaN-based HEMT device according to claim 1, wherein: the step of forming the single-crystal AlN barrier layer includes:

forming a sub AlN layer at the temperature of 260-320 ℃ by adopting atomic layer deposition;

carrying out plasma annealing by adopting Ar plasma to convert the sub AlN layer into a sub single crystal AlN barrier layer;

and circularly preparing the sub-single crystal AlN barrier layer to form the single crystal AlN barrier layer stacked by the sub-single crystal AlN barrier layer.

3. The method for manufacturing a GaN-based HEMT device according to claim 2, wherein: the time for plasma annealing by using Ar plasma comprises 10s-30s, and the power comprises 100W-300W.

4. The method for manufacturing a GaN-based HEMT device according to claim 1, wherein: the thickness of the monocrystalline AlN barrier layer is 7nm-9 nm.

5. The method of manufacturing a GaN-based HEMT device according to claim 1, wherein the step of forming said amorphous AlN passivation protection layer comprises:

forming a sub-amorphous AlN passivation protection layer at the temperature of 260-320 ℃ by adopting atomic layer deposition;

and circularly preparing the sub amorphous AlN passivation protection layer to form the amorphous AlN passivation protection layer stacked by the sub amorphous AlN passivation protection layer.

6. The method for manufacturing a GaN-based HEMT device according to claim 1, wherein: the step of forming the source and drain regions comprises a step of ion implantation with an energy of 40-70 KeV and a dose of 1e15/cm and a step of activation²-3e15/cm²The activation temperature includes 1050 deg.C-1250 deg.C.

7. The method for manufacturing a GaN-based HEMT device according to claim 1, wherein: the method also comprises a step of forming a gate electrode, wherein the step of forming the gate electrode comprises the step of etching the amorphous AlN passivation protection layer and the single-crystal AlN barrier layer to form the gate electrode which penetrates through the amorphous AlN passivation protection layer and the single-crystal AlN barrier layer and is in contact with the AlGaN barrier layer; or the gate electrode is formed when the source electrode and the drain electrode are formed.

8. The method for manufacturing a GaN-based HEMT device according to claim 1, wherein: the source electrode and the drain electrode are formed by adopting an ohmic contact electrode formed by adopting an annealing process, wherein the annealing temperature comprises 400-600 ℃.

9. A GaN-based HEMT device, comprising:

a substrate;

the epitaxial structure is positioned on the substrate and comprises a GaN layer and an AlGaN barrier layer which are superposed from bottom to top;

source and drain regions extending through the AlGaN barrier layer and having bottoms extending into the GaN layer;

a single crystal AlN barrier layer on the AlGaN barrier layer;

an amorphous AlN passivation protection layer on the single crystal AlN barrier layer;

and the source electrode and the drain electrode penetrate through the amorphous AlN passivation protective layer and the single-crystal AlN barrier layer and are respectively contacted with the corresponding source region and the corresponding drain region.

Technical Field

The invention belongs to the technical field of semiconductors, and relates to a GaN-based HEMT device and a preparation method thereof.

Background

Gallium Nitride (GaN) is a third-generation semiconductor material, and has been widely studied and applied due to its characteristics of large forbidden bandwidth (3.4 eV), high breakdown field strength, excellent thermal conductivity, and large electron saturation velocity. The High Electron Mobility Transistor (HEMT) based on the AlGaN/GaN heterojunction has spontaneous polarization and piezoelectric polarization effects, can generate High-density two-dimensional Electron gas without doping, has small scattering on electrons and High Mobility, and can be applied to High-frequency and High-power electronic devices with excellent performance.

The GaN-based HEMT device generally has a current collapse effect, which can reduce the working performance of the device, and the current collapse effect of the device can be improved to a certain extent by surface passivation treatment, wherein the passivation treatment comprises in-situ deposition or ex-situ deposition for forming an SiN medium or SiO₂Dielectric, or Al deposited by ALD₂O₃And a medium, etc., for mitigating current collapse by changing interface defects. Although conventional passivation techniques can improve surface defects to some extent, there is still a need for more effective ways to improve interface defects.

In addition, the GaN-based HEMT device also has a heat dissipation problem, and heat generated by the device is difficult to evacuate in time under a high-power working condition, so that the performance and reliability of the device are also affected. The conventional method for improving the heat dissipation problem includes bonding a metal heat sink on the back of the substrate or using diamond bonding to improve the heat dissipation of the device, but the process steps are complicated and the diamond is expensive.

Therefore, it is necessary to provide a GaN-based HEMT device and a method for fabricating the same to provide a more efficient and cheaper heat dissipation method.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a GaN-based HEMT device and a method for manufacturing the same, which are used to solve the problems of the prior art that the GaN-based HEMT device is difficult to improve surface defects and dissipate heat of the device.

In order to achieve the above and other related objects, the present invention provides a method for manufacturing a GaN-based HEMT device, comprising the steps of:

providing a substrate;

forming an epitaxial structure on the substrate, wherein the epitaxial structure comprises a GaN layer and an AlGaN barrier layer which are overlapped from bottom to top;

forming an SiN passivation protective layer covering the AlGaN barrier layer on the AlGaN barrier layer;

forming source and drain regions in the epitaxial structure, the source and drain regions penetrating through the AlGaN barrier layer and extending bottom into the GaN layer;

patterning the SiN passivation protection layer to expose the source region and the drain region;

forming a source electrode in contact with the source region and a drain electrode in contact with the drain region;

removing the SiN passivation protective layer, exposing the AlGaN barrier layer, and cleaning the surface of the AlGaN barrier layer;

forming a single crystal AlN barrier layer on the exposed AlGaN barrier layer by adopting an atomic layer deposition and plasma annealing process, and forming an amorphous AlN passivation protection layer on the single crystal AlN barrier layer by adopting the atomic layer deposition in the same deposition cavity;

and patterning the single-crystal AlN barrier layer and the amorphous AlN passivation protection layer to expose the source electrode and the drain electrode.

Optionally, the step of forming the single-crystal AlN barrier layer comprises:

forming a sub AlN layer at the temperature of 260-320 ℃ by adopting atomic layer deposition;

carrying out plasma annealing by adopting Ar plasma to convert the sub AlN layer into a sub single crystal AlN barrier layer;

and circularly preparing the sub-single crystal AlN barrier layer to form the single crystal AlN barrier layer stacked by the sub-single crystal AlN barrier layer.

Optionally, the plasma annealing with the Ar plasma is performed for 10s-30s, and the power is 100W-300W.

Optionally, the single-crystal AlN barrier layer is formed to a thickness of 7nm to 9 nm.

Optionally, the step of forming the amorphous AlN passivation protection layer includes:

forming a sub-amorphous AlN passivation protection layer at the temperature of 260-320 ℃ by adopting atomic layer deposition;

and circularly preparing the sub amorphous AlN passivation protection layer to form the amorphous AlN passivation protection layer stacked by the sub amorphous AlN passivation protection layer.

Optionally, the step of forming the source region and the drain region includes a step of ion implantation and a step of activation, wherein the energy of the ion implantation includes 40KeV to 70KeV, and the dose of the ion implantation includes 1e15/cm²-3e15/cm²The activation temperature includes 1050 deg.C-1250 deg.C.

Optionally, a step of forming a gate electrode is further included, wherein the step of forming the gate electrode includes etching the amorphous AlN passivation protection layer and the single-crystal AlN barrier layer to form a gate electrode penetrating through the amorphous AlN passivation protection layer and the single-crystal AlN barrier layer and contacting the AlGaN barrier layer; or the gate electrode is formed when the source electrode and the drain electrode are formed.

Optionally, the source electrode and the drain electrode are formed by ohmic contact electrodes formed by an annealing process, wherein the annealing temperature includes 400 ℃ to 600 ℃.

The present invention also provides a GaN-based HEMT device, comprising:

a substrate;

the epitaxial structure is positioned on the substrate and comprises a GaN layer and an AlGaN barrier layer which are superposed from bottom to top;

source and drain regions extending through the AlGaN barrier layer and having bottoms extending into the GaN layer;

a single crystal AlN barrier layer on the AlGaN barrier layer;

an amorphous AlN passivation protection layer on the single crystal AlN barrier layer;

and the source electrode and the drain electrode penetrate through the amorphous AlN passivation protective layer and the single-crystal AlN barrier layer and are respectively contacted with the corresponding source region and the corresponding drain region.

As mentioned above, the GaN-based HEMT device and the preparation method thereof of the invention, an epitaxial structure comprising a GaN layer and an AlGaN barrier layer which are overlapped from bottom to top and an SiN passivation protective layer covering the AlGaN barrier layer are firstly formed on a substrate, so as to protect the surface of the AlGaN barrier layer through the SiN passivation protective layer and avoid damaging the AlGaN barrier layer in the subsequent process, then a source region and a drain region are formed in the epitaxial structure, and corresponding source electrodes and drain electrodes are formed, then the SiN passivation protective layer is removed, the AlGaN barrier layer is exposed, after the surface of the AlGaN barrier layer is cleaned, a single crystal AlN barrier layer is formed on the exposed AlGaN barrier layer by adopting the processes of atomic layer deposition and plasma annealing, so that the amorphous or polycrystalline AlN layer deposited at low temperature is converted into an epitaxial single crystal AlN layer, thereby generating polarization effect on the AlGaN barrier layer to further modulate two-dimensional electron gas in the AlGaN barrier layer, and simultaneously forming a regional thin auxiliary channel (a region except an electrode part) in the AlGaN barrier layer, the distance from the gate electrode to the channel is not affected, so that the integral linearity of the device is improved, in the same deposition cavity, the atomic layer deposition is adopted to form the amorphous AlN passivation protection layer on the single crystal AlN barrier layer, and the continuous in-situ atomic layer deposition is adopted to deposit the single crystal and the amorphous AlN layer, so that the interface quality of the crystal AlN/amorphous AlN can be improved, the Pulse-IV characteristic of the device is optimized, meanwhile, the AlN layer has high heat conductivity and good heat dissipation performance, and the integral heat dissipation performance of the device can be improved.

Drawings

Fig. 1 is a schematic structural diagram of an epitaxial structure formed in an embodiment of the invention.

Fig. 2 is a schematic structural diagram of a SiN passivation protection layer formed in an embodiment of the invention.

Fig. 3 is a schematic structural diagram illustrating a source region and a drain region formed in an embodiment of the invention.

Fig. 4 is a schematic structural diagram of the source electrode and the drain electrode formed in the embodiment of the invention.

FIG. 5 is a schematic structural diagram illustrating the SiN passivation layer removed according to the embodiment of the present invention.

FIG. 6 is a schematic diagram of a single-crystal AlN barrier layer and an amorphous AlN passivation layer according to an embodiment of the present invention.

Fig. 7 is a schematic structural diagram after a gate electrode is formed in the embodiment of the invention.

Description of the element reference numerals

A 110-GaN layer; a 120-AlGaN barrier layer; 200-SiN passivation protection layer; 310-a source region; 320-a drain region; 410-a source electrode; 420-a drain electrode; 430-a gate electrode; 500-single crystal AlN barrier layer; 600-amorphous AlN passivation protection layer.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

As in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the device structures are not partially enlarged in general scale for convenience of illustration, and the schematic views are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

For convenience in description, spatial relational terms such as "below," "beneath," "below," "under," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Further, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. As used herein, "between … …" is meant to include both endpoints.

In the context of this application, a structure described as having a first feature "on" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.

It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of each component in actual implementation may be changed freely, and the layout of the components may be more complicated.

The embodiment provides a preparation method of a GaN-based HEMT device, which comprises the following steps:

s1: providing a substrate;

s2: forming an epitaxial structure on the substrate, wherein the epitaxial structure comprises a GaN layer and an AlGaN barrier layer which are overlapped from bottom to top;

s3: forming an SiN passivation protective layer covering the AlGaN barrier layer on the AlGaN barrier layer;

s4: forming source and drain regions in the epitaxial structure, the source and drain regions penetrating through the AlGaN barrier layer and extending bottom into the GaN layer;

s5: patterning the SiN passivation protection layer to expose the source region and the drain region;

s6: forming a source electrode in contact with the source region and a drain electrode in contact with the drain region;

s7: removing the SiN passivation protective layer, exposing the AlGaN barrier layer, and cleaning the surface of the AlGaN barrier layer;

s8: forming a single crystal AlN barrier layer on the exposed AlGaN barrier layer by adopting an atomic layer deposition and plasma annealing process, and forming an amorphous AlN passivation protection layer on the single crystal AlN barrier layer by adopting the atomic layer deposition in the same deposition cavity;

s9: and patterning the single-crystal AlN barrier layer and the amorphous AlN passivation protection layer to expose the source electrode and the drain electrode.

Specifically, referring to fig. 1 to 7, schematic structural diagrams of steps in the fabrication of the GaN-based HEMT device in this embodiment are shown.

First, step S1 is performed to provide a substrate (not shown).

Specifically, the substrate may include one of a Si substrate, a SiC substrate, and a sapphire substrate, and the kind of the substrate is not limited thereto. In the embodiment, because the Si substrate has the characteristics of large size, low price, and the like, the Si (111) substrate is preferably used as the substrate to meet the requirement of cost saving, and the Si substrate with (111) orientation is favorable for the growth of subsequent materials based on lattice adaptability. The size of the substrate can be 8-inch wafers, 12-inch wafers, etc., without being limited excessively.

Next, as shown in fig. 1, step S2 is performed to form an epitaxial structure on the substrate, wherein the epitaxial structure includes a GaN layer 110 and an AlGaN barrier layer 120 stacked from bottom to top.

Specifically, the epitaxial structure may include an AlN nucleation layer and a buffer layer on the substrate, so that the AlN nucleation layer serves as a seed layer, and the buffer layer may be used to alleviate lattice mismatch and thermal expansion coefficient mismatch between the GaN layer 110 and the substrate. Wherein the buffer layer may include one or a combination of an AlGaN buffer layer and a GaN buffer layer, and the AlGaN buffer layer may include a single layer or Al_xGa_1-xN laminated layers, wherein the value range of x can include 0 < x < 1 and is far away from Al of the GaN layer 110_xGa_1-xThe value of x of the N layer is larger than that of Al adjacent to the GaN layer 110_xGa_1-xThe value of x for the N layer to mitigate the lattice mismatch and coefficient of thermal expansion mismatch of the substrate and the GaN layer 110. After the AlGaN buffer layer is formed, the GaN buffer layer with high resistance can be formed to form a GaN device with good anti-leakage performance,and after the high-resistance GaN buffer layer is formed, an AlN back barrier layer can be formed, so that the concentration of two-dimensional electron gas is further improved through the self-polarization capability of the AlN back barrier layer, and a GaN device with good leak-proof performance and high breakdown voltage is prepared. The AlGaN barrier layer 120 may include Al_xGa_1-xAnd N layers, wherein x can be in a range of 0 < x < 1, and preferably x =0.3, but is not limited thereto. In this embodiment, to simplify the structure, the epitaxial structure only employs the GaN layer 110 and the AlGaN barrier layer 120 stacked in sequence, and the specific configuration of the epitaxial structure can be selected according to the requirement, which is not limited herein.

Next, as shown in fig. 2, step S3 is performed to form a SiN passivation protection layer 200 on the AlGaN barrier layer 120 to cover the AlGaN barrier layer 120.

Specifically, the SiN passivation protection layer 200 may be deposited by an LPCVD method or a PECVD method, so as to protect the surface of the AlGaN barrier layer 120 through the formed SiN passivation protection layer 200, thereby preventing the AlGaN barrier layer 120 from being damaged by a subsequent process.

Next, as shown in fig. 3, step S4 is performed to form a source region 310 and a drain region 320 in the epitaxial structure, wherein the source region 310 and the drain region 320 penetrate through the AlGaN barrier layer 120 and extend to the bottom into the GaN layer 110.

As an example, the steps of forming the source region 310 and the drain region 320 include ion implantation and activation, wherein the energy of the ion implantation includes 40KeV to 70KeV, and the dose of the ion implantation includes 1e15/cm²-3e15/cm²The activation temperature includes 1050 deg.C-1250 deg.C.

Specifically, in the present embodiment, the source region 310 and the drain region 320 are n⁺Highly doped region for forming a low ohmic contact resistance, wherein the energy of the ion implantation may include 40KeV-70KeV, such as 40KeV, 50KeV, 60KeV, 70KeV, etc., and the dose of the ion implantation may include 1e15/cm²-3e15/cm²E.g. 1e15/cm²、2e15/cm²、3e15/cm²Etc., the activation temperature may include 1050 deg.C-1250 deg.C, such as 1050 deg.C,1100 ℃, 1150 ℃, 1200 ℃, 1250 ℃, etc., so that the SiN passivation protection layer 200 can effectively protect the AlGaN barrier layer 120 at high activation temperatures, avoiding high temperature dissociation of the AlGaN barrier layer 120.

Next, as shown in fig. 4, step S5 is performed to pattern the SiN passivation protection layer 200 to expose the source region 310 and the drain region 320, and step S6 is performed to form a source electrode 410 in contact with the source region 310 and a drain electrode 420 in contact with the drain region 320.

As an example, the source electrode 410 and the drain electrode 420 are formed as ohmic contact electrodes by using an annealing process, wherein the annealing temperature includes 400 ℃ to 600 ℃.

Specifically, in this embodiment, a dry ICP is used to remove a portion of the SiN passivation protection layer 200 to expose the source region 310 and the drain region 320, and then a deposition method is used to form the source electrode 410 in contact with the source region 310 and the drain electrode 420 in contact with the drain region 320, wherein preferably, the source electrode 410 and the drain electrode 420 are made of a metal material, and an annealing process is used to form an ohmic contact electrode in contact with the corresponding source region 310 and the corresponding drain region 320. The annealing temperature can include 400 ℃, 500 ℃, 600 ℃ and the like, and can be specifically selected according to needs.

Next, as shown in fig. 5, step S7 is performed to remove the SiN passivation protection layer 200, expose the AlGaN barrier layer 120, and clean the surface of the AlGaN barrier layer 120.

Specifically, the SiN passivation protection layer 200 may be removed by a wet BOE etching process, and then the surface of the AlGaN barrier layer 120 is cleaned by TMAH to remove impurities, and then the AlGaN passivation protection layer is sent to a deposition chamber of atomic layer deposition (PEALD).

Next, as shown in fig. 6, step S8 is performed, a single-crystal AlN barrier layer 500 is formed on the exposed AlGaN barrier layer 120 by using atomic layer deposition and plasma annealing, and an amorphous AlN passivation protection layer 600 is formed on the single-crystal AlN barrier layer 500 by using atomic layer deposition in the same deposition chamber.

As an example, the step of forming the single-crystal AlN barrier layer 500 may include:

forming a sub AlN layer at the temperature of 260-320 ℃ by adopting a PEALD method;

carrying out plasma annealing by adopting Ar plasma to convert the sub AlN layer into a sub single crystal AlN barrier layer;

and circularly preparing the sub-single-crystal AlN barrier layer to form the single-crystal AlN barrier layer 500 stacked by the sub-single-crystal AlN barrier layer.

Specifically, forming the single-crystal AlN barrier layer 500 may include a plurality of cycling operations, each cycling operation including the steps of:

firstly, introducing TMA gas as an Al gas source;

secondly, introducing Ar for impurity removal;

thirdly, introducing H₂/N₂Plasma as N gas source;

fourthly, introducing Ar to remove impurities;

and fifthly, introducing Ar plasma for plasma annealing.

This is cycled to form the single crystal AlN barrier layer 500, wherein the surface of the AlGaN barrier layer 120 is cleaned in situ, e.g., with NH, in PEALD prior to deposition₃、Ar、N₂And cleaning the surface of the AlGaN barrier layer 120 for 30s-1min respectively and with the power of 100W-300W in sequence, then depositing AlN to form a sub-AlN layer, and then performing a circulation step. Each cycle step comprises Ar plasma annealing for 10s-30s, such as 10s, 20s, 30s, etc., and with a power of 100W-300W, such as 100W, 200W, 300W, etc., so that annealing with Ar plasma in each cycle step is performed in order to convert the amorphous or polycrystalline AlN layer deposited by low temperature ALD into a sub-single crystal AlN barrier layer to finally form the single crystal AlN barrier layer 500, thereby generating polarization on the AlGaN barrier layer 120 to further modulate the two-dimensional electron gas in the GaN layer 110, and simultaneously forming a thin auxiliary channel regionally on the AlGaN barrier layer 120, which can improve the overall linearity of the device.

It is noted that conventional low temperature ALD deposits an amorphous or polycrystalline AlN layer, and thus cannot polarize the AlGaN barrier layer 120, and plasma annealing can transform the amorphous or polycrystalline AlN layer into a single crystal AlN film, which can serve as a barrier layer, thereby forming a stacked barrier structure of the AlGaN barrier layer 120 with the 1 st barrier layer and the single crystal AlN barrier layer 500 with the 2 nd barrier layer, and further modulating the two-dimensional electron gas in the GaN device.

By way of example, the single-crystal AlN barrier layer 500 may be formed to a thickness of 7nm to 9nm, e.g., 7nm, 8nm, 9nm, etc., after completing 100 cycles of the steps, and the specific thickness may be set according to the selection of the number of cycles of the steps.

As an example, the step of forming the amorphous AlN passivation protection layer 600 includes:

forming a sub-amorphous AlN passivation protective layer at the temperature of 260-320 ℃ by adopting a PEALD method;

and circularly preparing the sub amorphous AlN passivation protection layer to form the amorphous AlN passivation protection layer 600 stacked by the sub amorphous AlN passivation protection layer.

Specifically, after 100 cycles of steps are performed to prepare the single crystal AlN barrier layer 500, the amorphous AlN passivation protection layer 600 is preferably formed in the same deposition chamber, for example, 200 cycles of deposition are continued, and during the 200 cycles of deposition, Ar plasma annealing is not performed, so that an amorphous AlN dielectric layer may be formed as a surface passivation protection layer, i.e., the amorphous AlN passivation protection layer 600. The amorphous AlN passivation protection layer 600 is used as a surface passivation layer to improve the quality of a crystal AlN/amorphous AlN interface, and further, the PEALD deposition process is a continuous in-situ process, so that the PIV characteristic of a GaN device can be optimized, and meanwhile, the AlN layer has high thermal conductivity, good heat dissipation performance and can also improve the overall heat dissipation performance of the GaN device.

It is emphasized that when the single crystal AlN barrier layer 500 and the amorphous AlN passivation protection layer 600 are deposited using PEALD and completed in the same deposition chamber, the AlN/AlN interface defects formed may be improved to the greatest extent since the intermediate sample does not leave the deposition chamber, thereby reducing the current collapse effect caused by the defects, and the amorphous AlN as a passivation layer may improve the surface heat dissipation of the GaN device due to its high thermal conductivity.

Next, as shown in fig. 6, step S9 is performed to pattern the single-crystal AlN barrier layer and the amorphous AlN passivation protection layer 600, exposing the source electrode 410 and the drain electrode 420.

Further, as shown in fig. 7, a step of forming a gate electrode 430 is further included, wherein the step of forming the gate electrode 430 includes etching the amorphous AlN passivation protection layer 600 and the single-crystal AlN barrier layer 500 to form the gate electrode 430 penetrating through the amorphous AlN passivation protection layer 600 and the single-crystal AlN barrier layer 500, but is not limited thereto, and the gate electrode 430 may be formed when forming the source electrode 410 and the drain electrode 420, that is, the gate electrode 430 is first prepared, and then deposition of AlN is performed, wherein the gate electrode 430 may be made of a metal material, and the gate electrode 430 made of a metal material is not damaged due to a low deposition temperature of AlN, and the preparation of the gate electrode 430 may be selected as needed.

As shown in fig. 7, the present embodiment also provides a GaN-based HEMT device including a substrate, an epitaxial structure, a source region 310, a drain region 320, a single-crystal AlN barrier layer 500, and an amorphous AlN passivation protection layer 600. The epitaxial structure is located on the substrate, the epitaxial structure comprises a GaN layer 110 and an AlGaN barrier layer 120 which are stacked from bottom to top, the source region 310 and the drain region 320 penetrate through the AlGaN barrier layer 120, the bottom of the source region extends into the GaN layer 110, the single crystal AlN barrier layer 500 is located on the AlGaN barrier layer 120, the amorphous AlN passivation protection layer 600 is located on the single crystal AlN barrier layer 500, and the source electrode 410 and the drain electrode 420 penetrate through the amorphous AlN passivation protection layer 600 and the single crystal AlN barrier layer 500 and are respectively in contact with the corresponding source region 310 and the corresponding drain region 320. The materials and the preparation method of the GaN-based HEMT device can refer to the preparation process, and are not described herein.

In summary, the GaN-based HEMT device and the method for manufacturing the same of the present invention, an epitaxial structure including a GaN layer and an AlGaN barrier layer stacked from bottom to top and an SiN passivation protective layer covering the AlGaN barrier layer are formed on a substrate to protect the surface of the AlGaN barrier layer through the SiN passivation protective layer to prevent the AlGaN barrier layer from being damaged in the subsequent processes, then a source region and a drain region are formed in the epitaxial structure, and corresponding source and drain electrodes are formed, then the SiN passivation protective layer is removed to expose the AlGaN barrier layer, and after the surface of the AlGaN barrier layer is cleaned, a single crystal AlN barrier layer is formed on the exposed AlGaN barrier layer by using atomic layer deposition and plasma annealing processes to convert the amorphous or polycrystalline AlN layer deposited at low temperature into an epitaxial single crystal AlN layer, thereby generating a polarization effect on the AlGaN barrier layer to further modulate two-dimensional electron gas in the channel, and simultaneously forming a regional thin auxiliary channel (a region except for an electrode portion) in the AlGaN barrier layer, the distance from the gate electrode to the channel is not affected, so that the integral linearity of the device is improved, in the same deposition cavity, the atomic layer deposition is adopted to form the amorphous AlN passivation protection layer on the single crystal AlN barrier layer, and the continuous in-situ atomic layer deposition is adopted to deposit the single crystal and the amorphous AlN layer, so that the interface quality of the crystal AlN/amorphous AlN can be improved, the Pulse-IV characteristic of the device is optimized, meanwhile, the AlN layer has high heat conductivity and good heat dissipation performance, and the integral heat dissipation performance of the device can be improved.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.