CN108767018B - Epitaxial structure and process method for manufacturing high-frequency GaN-based thin film Schottky device - Google Patents
Epitaxial structure and process method for manufacturing high-frequency GaN-based thin film Schottky device Download PDFInfo
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- H01L29/66212—Schottky diodes
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Abstract
The invention belongs to the technical field of terahertz high-frequency devices, and discloses an epitaxial structure and a process method for manufacturing a high-frequency GaN-based thin film Schottky device, wherein the epitaxial structure is a structure I or a structure II: the first structure comprises a substrate, a buffer layer, a current expansion layer, a GaN sacrificial layer and a Schottky active layer; a low-resistance conductive channel is formed between the current expansion layer and the GaN sacrificial layer; the second structure comprises a substrate, a buffer layer, a GaN sacrificial layer and a Schottky active layer; a low-resistance conductive channel is formed between the Schottky active layer and the GaN sacrificial layer; the process method comprises the steps of depositing an insulating medium layer, enabling a low-resistance conducting channel to be formed between an ohmic electrode table-board and a GaN sacrificial layer, forming an ohmic contact metal electrode of the Schottky device on the n + GaN layer, preparing the exposed GaN sacrificial layer, stripping a GaN-based Schottky active layer from a substrate, manufacturing the Schottky contact metal electrode on the Schottky active layer and interconnecting metal to finish the manufacturing of the high-frequency GaN-based thin film Schottky device.
Description
Technical Field
The invention belongs to the technical field of terahertz high-frequency devices, and particularly relates to an epitaxial structure and a process method for manufacturing a high-frequency GaN-based thin film Schottky device.
Background
The terahertz (THz) wave is defined between 0.1THz and 10THz and is between microwave and infrared, and has extremely important academic value and practical significance. At present, the GaN-based Schottky device with the terahertz waveband needs to be manufactured by thinning and polishing the substrate. However, GaN material has the characteristics of strong chemical inertness and strong mechanical hardness, which makes the substrate thinning process of GaN material extremely difficult. One solution is to peel off the GaN epitaxial layer from the substrate by laser lift-off, however, the laser lift-off method is expensive, the bottom of the epitaxial layer after lift-off is very uneven, chemical polishing is required to flatten the peel-off surface, and laser irradiation may affect the device active region and thus affect the device performance.
Disclosure of Invention
In order to solve the above problems in the prior art, the present invention is directed to an epitaxial structure and a process for manufacturing a high frequency GaN-based thin film schottky device.
The technical scheme adopted by the invention is as follows:
an epitaxial structure for manufacturing a high-frequency GaN-based thin film Schottky device is characterized in that the epitaxial structure is a structure I or a structure II:
the first structure comprises a substrate, a buffer layer, a current expansion layer, a GaN sacrificial layer and a Schottky active layer; the substrate, the buffer layer, the current expansion layer, the GaN sacrificial layer and the Schottky active layer are sequentially connected; the current expansion layer and the GaN sacrificial layer are both high-conductivity layers, and a low-resistance conductive channel is formed between the current expansion layer and the GaN sacrificial layer;
the second structure comprises a substrate, a buffer layer, a GaN sacrificial layer and a Schottky active layer; the substrate, the buffer layer, the GaN sacrificial layer and the Schottky active layer are sequentially connected; and a low-resistance conductive channel is formed between the Schottky active layer and the GaN sacrificial layer.
Further, when the epitaxial structure is the first structure or the second structure, the substrate is made of GaN, Si, sapphire or SiC materials.
Furthermore, when the epitaxial structure is the first structure or the second structure, the buffer layer is made of GaN, InGaN, AlGaN or AlN material.
Further, when the epitaxial structure is a structural example, the current spreading layer is made of GaN, InGaN, AlGaN or AlN material, and the doping concentration of the current spreading layer is more than 1 × 1018/cm3The thickness of the current spreading layer is 0.1-3 μm.
Furthermore, when the epitaxial structure is in a first structure, the electric conductance of the GaN sacrificial layer is larger than the electric conductance of the current expansion layer and the Schottky active layer, and the thickness of the GaN sacrificial layer is 0.1-3 mu m.
Furthermore, when the epitaxial structure is the first structure or the second structure, the GaN sacrificial layer is made of materials with corrosion selectivity higher than that of the substrate, the buffer layer, the current expansion layer and the Schottky active layer, and the electrochemical corrosion rate of the GaN sacrificial layer is more than 10 times of the corrosion rate of the buffer layer, the current expansion layer and the Schottky active layer.
Furthermore, when the epitaxial structure is a structure I or a structure II, the Schottky active layers are sequentially connectedAn n-GaN layer and an n + GaN layer; the n + GaN layer or the n-GaN layer is connected with the GaN sacrificial layer; the doping impurity of the n-GaN layer is Si with a doping concentration of 1 × 1016/cm3~1×1018/cm3The thickness of the n-GaN layer is 0.05-1 μm; the doped impurity of the n + GaN layer is Si, and the doping concentration is more than 1 × 1018/cm3The thickness range is 0.05-5 μm; when the epitaxial structure is a structure II, the n + GaN layer and the GaN sacrificial layer are high-conductivity layers; the n + GaN layer is connected with the GaN sacrificial layer, and a low-resistance conductive channel is formed between the n + GaN layer and the GaN sacrificial layer.
A process method for manufacturing an epitaxial structure of a high-frequency GaN-based thin film Schottky device comprises the following steps when the epitaxial structure is in a first structure:
A) depositing an insulating medium layer on the upper surface of the Schottky active layer of the epitaxial structure;
B) forming an electrode window on the surface of the insulating medium layer by photoetching and etching, and etching the electrode window downwards to form an ohmic electrode table-board on the current expansion layer, so that a low-resistance conductive channel is formed between the ohmic electrode table-board and the GaN sacrificial layer;
C) forming an ohmic contact metal electrode of the Schottky device on the n + GaN layer;
D) exposing partial surface or/and side wall of the GaN sacrificial layer to obtain an exposed GaN sacrificial layer;
E) carrying out electrochemical corrosion on the exposed GaN sacrificial layer to strip the GaN-based Schottky active layer from the substrate;
F) and manufacturing a Schottky contact metal electrode to finish the manufacture of the high-frequency GaN-based thin film Schottky device.
A process method for manufacturing an epitaxial structure of a high-frequency GaN-based thin film Schottky device comprises the steps that when the epitaxial structure is a structure II, an n + GaN layer is connected with a GaN sacrificial layer; the method comprises the following steps:
A) depositing an insulating medium layer on the upper surface of the n-GaN layer of the epitaxial structure;
B) forming an ohmic contact metal electrode and an ohmic electrode mesa on the n + GaN layer;
C) exposing partial surface or/and side wall of the GaN sacrificial layer to obtain an exposed GaN sacrificial layer;
D) carrying out electrochemical corrosion on the exposed GaN sacrificial layer to strip the GaN-based Schottky active layer from the substrate;
E) and manufacturing a Schottky contact metal electrode to finish the manufacture of the high-frequency GaN-based thin film Schottky device.
The invention has the beneficial effects that: the GaN film obtained by the epitaxial structure and the process method is complete, basically free of damage and small in thickness, and can be transferred to other substrates.
Drawings
FIG. 1 is a side view of a first structure of the present invention.
Fig. 2 is a schematic side view of the high frequency GaN-based thin film schottky device fabricated using the first epitaxial structure of the present invention after the step D.
Fig. 3 is a schematic side view of the high frequency GaN-based thin film schottky device fabricated using the first epitaxial structure of the present invention, after step E.
Fig. 4 is a schematic side view of the completed high frequency GaN-based thin film schottky device of the present invention using the epitaxial structure one.
FIG. 5 is a side view of a second structure of the present invention.
Fig. 6 is a schematic side view of the high frequency GaN-based thin film schottky device fabricated using epitaxial structure two of the present invention after step C.
Fig. 7 is a schematic side view of the high frequency GaN-based thin film schottky device fabricated using epitaxial structure two through step D of the present invention.
Fig. 8 is a schematic side view of the completed high frequency GaN-based thin film schottky device using epitaxial structure two of the present invention.
In the figure: 11-a first substrate; 12-a first buffer layer; 13-a first current spreading layer; 14-a first GaN sacrificial layer; 15-a first n + GaN layer; 16-a first n-GaN layer; 17-a first insulating dielectric layer; 18-a first ohmic electrode mesa; 19-a first ohmic contact metal; 110-a first schottky metal; 111-first device air bridge outgoing pad; 21-a second substrate; 22-a second buffer layer; 24-a second GaN sacrificial layer; 25-a second n + GaN layer; 26-a second n-GaN layer; 27-a second insulating dielectric layer; 28-a second ohmic electrode mesa; 29-a second ohmic contact metal; 210-a second schottky metal; 211-second device air bridge outgoing pad.
Detailed Description
The invention is further explained below with reference to the drawings and the specific embodiments.
An epitaxial structure for manufacturing a high-frequency GaN-based thin film Schottky device is characterized in that the epitaxial structure is a structure I or a structure II:
the first structure comprises a substrate, a buffer layer, a current expansion layer, a GaN sacrificial layer and a Schottky active layer; the substrate, the buffer layer, the current expansion layer, the GaN sacrificial layer and the Schottky active layer are sequentially connected; the current expansion layer and the GaN sacrificial layer are both high-conductivity layers, and a low-resistance conductive channel is formed between the current expansion layer and the GaN sacrificial layer;
the second structure comprises a substrate, a buffer layer, a GaN sacrificial layer and a Schottky active layer; the substrate, the buffer layer, the GaN sacrificial layer and the Schottky active layer are sequentially connected; and a low-resistance conductive channel is formed between the Schottky active layer and the GaN sacrificial layer.
Further, when the epitaxial structure is the first structure or the second structure, the substrate is made of GaN, Si, sapphire or SiC materials.
Furthermore, when the epitaxial structure is the first structure or the second structure, the buffer layer is made of GaN, InGaN, AlGaN or AlN material.
Further, when the epitaxial structure is a structural example, the current spreading layer is made of GaN, InGaN, AlGaN or AlN material, and the doping concentration of the current spreading layer is more than 1 × 1018/cm3The thickness of the current spreading layer is 0.1-3 μm.
Furthermore, when the epitaxial structure is in a first structure, the electric conductance of the GaN sacrificial layer is larger than the electric conductance of the current expansion layer and the Schottky active layer, and the thickness of the GaN sacrificial layer is 0.1-3 mu m.
Furthermore, when the epitaxial structure is the first structure or the second structure, the GaN sacrificial layer is made of materials with corrosion selectivity higher than that of the substrate, the buffer layer, the current expansion layer and the Schottky active layer, and the electrochemical corrosion rate of the GaN sacrificial layer is more than 10 times of the corrosion rate of the buffer layer, the current expansion layer and the Schottky active layer.
Further, when the epitaxial structure is a structure I or a structure II, the Schottky active layer comprises an n-GaN layer and an n + GaN layer which are sequentially connected; the n + GaN layer or the n-GaN layer is connected with the GaN sacrificial layer; the doping impurity of the n-GaN layer is Si with a doping concentration of 1 × 1016/cm3~1×1018/cm3The thickness of the n-GaN layer is 0.05-1 μm; the doped impurity of the n + GaN layer is Si, and the doping concentration is more than 1 × 1018/cm3The thickness range is 0.05-5 μm; when the epitaxial structure is a structure II, the n + GaN layer and the GaN sacrificial layer are high-conductivity layers; the n + GaN layer is connected with the GaN sacrificial layer, and a low-resistance conductive channel is formed between the n + GaN layer and the GaN sacrificial layer.
A process method for manufacturing an epitaxial structure of a high-frequency GaN-based thin film Schottky device comprises the following steps when the epitaxial structure is in a first structure:
A) depositing an insulating medium layer on the upper surface of the Schottky active layer of the epitaxial structure;
B) forming an electrode window on the surface of the insulating medium layer by photoetching and etching, and etching the electrode window downwards to form an ohmic electrode table-board on the current expansion layer, so that a low-resistance conductive channel is formed between the ohmic electrode table-board and the GaN sacrificial layer;
C) forming an ohmic contact metal electrode of the Schottky device on the n + GaN layer;
D) exposing partial surface or/and side wall of the GaN sacrificial layer to obtain an exposed GaN sacrificial layer;
E) carrying out electrochemical corrosion on the exposed GaN sacrificial layer to strip the GaN-based Schottky active layer from the substrate;
F) and manufacturing a Schottky contact metal electrode to finish the manufacture of the high-frequency GaN-based thin film Schottky device.
According to the specific process flow design, the steps can be replaced and combined front and back to complete the manufacture of the high-frequency GaN-based thin film Schottky device.
A process method for manufacturing an epitaxial structure of a high-frequency GaN-based thin film Schottky device comprises the steps that when the epitaxial structure is a structure II, an n + GaN layer is connected with a GaN sacrificial layer; the method comprises the following steps:
A) depositing an insulating medium layer on the upper surface of the n-GaN layer of the epitaxial structure;
B) forming an ohmic contact metal electrode and an ohmic electrode mesa on the n + GaN layer;
C) exposing partial surface or/and side wall of the GaN sacrificial layer to obtain an exposed GaN sacrificial layer;
D) carrying out electrochemical corrosion on the exposed GaN sacrificial layer to strip the GaN-based Schottky active layer from the substrate;
E) and manufacturing a Schottky contact metal electrode to finish the manufacture of the high-frequency GaN-based thin film Schottky device.
According to the specific process flow design, the steps can be replaced and combined front and back to complete the manufacture of the high-frequency GaN-based thin film Schottky device.
Example 1
The embodiment discloses a first epitaxial structure for manufacturing a high-frequency GaN-based thin film Schottky device. As shown in fig. 1, it includes, from bottom to top:
the first substrate 11 is made of one of nonpolar, semipolar or polar GaN, Si, sapphire and SiC, and may be conductive or non-conductive, and is preferably a conductive substrate.
The first buffer layer 12 is made of one of GaN, InGaN, AlGaN, and AlN, and may be conductive or non-conductive, and a conductive material is preferably used.
The first current spreading layer 13 is made of one of GaN, InGaN, AlGaN and AlN, doped with Si with a doping concentration of more than 1 × 1018/cm3And the thickness is 0.1-3 μm.
The first GaN sacrificial layer 14 has high selective corrosion characteristics which are obviously different from those of the first substrate, the first buffer layer, the first current spreading layer and the first Schottky active layer, and the corrosion selectivity ratio is more than 10: 1; the doping impurity of the first GaN sacrificial layer is Si, and the doping concentration is more than 1 × 1018/cm3And the thickness is 0.1-3 μm. Wherein, a low resistance conduction is formed between the first current spreading layer 13 and the first GaN sacrificial layer 14A channel.
The first Schottky active layer comprises a first n + GaN layer 15 doped with Si at a concentration of more than 1 × 1018/cm3And the thickness is 0.5-5 μm.
The first Schottky active layer comprises a first n-GaN layer 16 doped with Si at a concentration of 1 × 1016/cm3~1×1018/cm3And the thickness is 0.05-1 μm.
Wherein the upper and lower order of the first n + GaN layer 15 and the first n-GaN layer 16 in the first schottky active layer can be exchanged, and if necessary, can also be used as a current blocking layer for blocking the current path between the first schottky active layer and the first GaN sacrificial layer 14.
As shown in fig. 1-4, the present invention provides a method for manufacturing a high frequency GaN-based thin film schottky device using the structure one, comprising the steps of:
A) depositing a first insulating dielectric layer 17 (refer to fig. 2) on the upper surface of the first n-GaN layer 16, wherein the material of the first insulating dielectric layer is PECVD SiO2The thickness is 50nm-1 μm. SiNx or photoresist may also be used as the material of the first insulating dielectric layer 17;
B) an electrode window is formed on the surface of the first insulating dielectric layer 17 by photolithography and etching. Etching the electrode window downward by using an ICP dry etching technique to form a first ohmic electrode mesa 18 (see fig. 2) on the first current spreading layer 13;
C) forming a first ohmic contact metal 19 (see fig. 2) on the first n + GaN layer 15 by photolithography, ICP dry etching, metal deposition, annealing, and the like, wherein the metal stack is Ti/Al/Ni/Au, or Ti/Al/Pd/Au, Ti/Al/Pt/Au, Ti/Al/Ti/Au, or the like;
D) forming a corrosion window on the surface of the first insulating medium layer 17 by photoetching and etching, and etching the corrosion window downwards until the side wall of the highly doped first GaN sacrificial layer 14 is exposed to form a corrosion through hole (refer to fig. 2);
E) clamping the first ohmic electrode mesa 18 using a metal crocodile mouth clamp, with a metal Pt sheet as the cathode and oxalic acid as the electrolyte, at constant voltage (5-30V) to the exposed side wallThe first GaN sacrificial layer 14 is electrochemically etched for a sufficient time to achieve the peeling of the GaN-based schottky active layer film from the substrate (see fig. 3). The electrolyte for electrochemical corrosion can also use HNO3、H3PO4、H2SO4KOH, etc.;
F) the manufacturing process of the on-chip schottky device is completed through the processes of GaN etching, first schottky metal 110 deposition, first device air bridge leading-out pad111 and the like (refer to fig. 4).
Example 2
The embodiment discloses a second epitaxial structure for manufacturing a high-frequency GaN-based thin film Schottky device. As shown in fig. 5, it includes, from bottom to top:
a second substrate 21 made of one of nonpolar, semipolar or polar GaN, Si, sapphire and SiC;
a second buffer layer 22 made of one of GaN, InGaN, AlGaN, and AlN;
the second GaN sacrificial layer 24 is a material having a high selective etching characteristic, which is clearly distinguished from the second schottky active layer, and is easily etched, and the etching selectivity ratio of the second GaN sacrificial layer to the second schottky active layer is greater than 10: 1; the doping impurity of the second GaN sacrificial layer is Si, and the doping concentration is more than 1 × 1018/cm3And is higher than the second Schottky active layer, and the thickness is 0.1-3 μm;
the second Schottky active layer comprises a second n + GaN layer 25 doped with Si at a concentration of more than 1 × 1018/cm3And the thickness is 0.5-5 μm. Wherein, the second schottky active layer comprises a low resistance conductive channel formed between the second n + GaN layer 25 and the second GaN sacrificial layer 24.
The second Schottky active layer comprises a second n-GaN layer 26 doped with Si at a concentration of 1 × 1016/cm3~1×1018/cm3The thickness is 0.05-1 μm.
Referring to fig. 6-8 in combination with fig. 5, the present invention provides a method for fabricating a high frequency GaN-based thin film schottky device using the second epitaxial structure, which comprises the following steps:
A) depositing a second insulating dielectric layer 27 (see FIG. 6) on the upper surface of the second n-GaN layer 26, wherein the material of the second insulating dielectric layer is PECVD SiO2The thickness is 0.05-1 μm. SiNx or photoresist may also be used as the material of the second insulating dielectric layer 27;
B) a second ohmic contact metal 29 (see fig. 6) is formed on the second n + GaN layer 25 by photolithography, ICP dry etching, metal deposition, annealing, etc., using a metal stack of Ti/Al/Ni/Au, or Ti/Al/Pd/Au, Ti/Al/Pt/Au, Ti/Al/Ti/Au, etc. A second ohmic electrode mesa 28 is also formed on the second n + GaN layer 25 (see fig. 6);
C) an etch window is formed on the surface of the second insulating dielectric layer 27 by photolithography and etching, and the etch window is etched down until the sidewalls of the second GaN sacrificial layer 24 are exposed to form an etch via (see fig. 6).
D) The second ohmic electrode mesa 28 was held by a metal alligator clip, the second GaN sacrificial layer 24 with exposed sidewalls was electrochemically etched at constant voltage (5-30V) using a metal Pt sheet as the cathode and oxalic acid as the electrolyte for a sufficient time to achieve peeling of the GaN-based schottky active layer film from the substrate (see fig. 7). The electrolyte for electrochemical corrosion can also use HNO3、H3PO4、H2SO4KOH, etc.;
E) the manufacturing process of the on-chip schottky device is completed through the processes of GaN etching, second schottky metal 210 deposition, second device air bridge leading-out pad211 and the like (refer to fig. 8).
The present invention is not limited to the above-described alternative embodiments, and various other forms of products can be obtained by anyone in light of the present invention. The above detailed description should not be taken as limiting the scope of the invention, which is defined in the claims, and which the description is intended to be interpreted accordingly.
Claims (7)
1. The utility model provides a preparation high frequency GaN base film schottky device's epitaxial structure which characterized in that: the epitaxial structure is a structure I or a structure II:
the first structure comprises a substrate, a buffer layer, a current expansion layer, a GaN sacrificial layer and a Schottky active layer; the substrate, the buffer layer, the current expansion layer, the GaN sacrificial layer and the Schottky active layer are sequentially connected; the current expansion layer and the GaN sacrificial layer are both high-conductivity layers, and a low-resistance conductive channel is formed between the current expansion layer and the GaN sacrificial layer;
the second structure comprises a substrate, a buffer layer, a GaN sacrificial layer and a Schottky active layer; the substrate, the buffer layer, the GaN sacrificial layer and the Schottky active layer are sequentially connected; a low-resistance conductive channel is formed between the Schottky active layer and the GaN sacrificial layer;
when the epitaxial structure is a first structure or a second structure, the Schottky active layer comprises an n-GaN layer and an n + GaN layer which are sequentially connected; the n + GaN layer or the n-GaN layer is connected with the GaN sacrificial layer; the doping impurity of the n-GaN layer is Si with a doping concentration of 1 × 1016/cm3~1×1018/cm3The thickness of the n-GaN layer is 0.05-1 μm; the doped impurity of the n + GaN layer is Si, and the doping concentration is more than 1 × 1018/cm3The thickness range is 0.05-5 μm; when the epitaxial structure is a structure II, the n + GaN layer and the GaN sacrificial layer are high-conductivity layers; the n + GaN layer is connected with the GaN sacrificial layer, and a low-resistance conductive channel is formed between the n + GaN layer and the GaN sacrificial layer;
when the epitaxial structure is the structure I or the structure II, the GaN sacrificial layer is made of materials with corrosion selectivity higher than that of the substrate, the buffer layer, the current expansion layer and the Schottky active layer, and the electrochemical corrosion rate of the GaN sacrificial layer is more than 10 times of the corrosion rate of the buffer layer, the current expansion layer and the Schottky active layer.
2. The epitaxial structure of claim 1, wherein the epitaxial structure is used for manufacturing a high frequency GaN-based thin film Schottky device, and is characterized in that: when the epitaxial structure is the first structure or the second structure, the substrate is made of GaN, Si, sapphire or SiC materials.
3. The epitaxial structure for forming a high frequency GaN-based thin film schottky device as claimed in claim 1 or 2, wherein: when the epitaxial structure is the first structure or the second structure, the buffer layer is made of GaN, InGaN, AlGaN or AlN materials.
4. The epitaxial structure for forming a high frequency GaN-based thin film schottky device as claimed in claim 1 or 2, wherein: when the epitaxial structure is a structural one, the current expansion layer is made of GaN, InGaN, AlGaN or AlN materials, and the doping concentration of the current expansion layer is more than 1 multiplied by 1018/cm3The thickness of the current spreading layer is 0.1-3 μm.
5. The epitaxial structure of claim 4, wherein the epitaxial structure is used for manufacturing a high frequency GaN-based thin film Schottky device, and is characterized in that: when the epitaxial structure is in a first structure, the electric conductance of the GaN sacrificial layer is larger than the electric conductance of the current expansion layer and the Schottky active layer, and the thickness of the GaN sacrificial layer is 0.1-3 mu m.
6. A process method of fabricating an epitaxial structure of a high frequency GaN-based thin film schottky device as claimed in claim 1, wherein: when the epitaxial structure is a structure I, the method comprises the following steps:
A) depositing an insulating medium layer on the upper surface of the Schottky active layer of the epitaxial structure;
B) forming an electrode window on the surface of the insulating medium layer by photoetching and etching, and etching the electrode window downwards to form an ohmic electrode table-board on the current expansion layer, so that a low-resistance conductive channel is formed between the ohmic electrode table-board and the GaN sacrificial layer;
C) forming an ohmic contact metal electrode of the Schottky device on the n + GaN layer;
D) exposing partial surface or/and side wall of the GaN sacrificial layer to obtain an exposed GaN sacrificial layer;
E) carrying out electrochemical corrosion on the exposed GaN sacrificial layer to strip the GaN-based Schottky active layer from the substrate;
F) and manufacturing a Schottky contact metal electrode to finish the manufacture of the high-frequency GaN-based thin film Schottky device.
7. A process method for manufacturing the epitaxial structure of the high-frequency GaN-based thin film Schottky device according to claim 6, characterized in that: when the epitaxial structure is a structure II, the n + GaN layer is connected with the GaN sacrificial layer; the method comprises the following steps:
A) depositing an insulating medium layer on the upper surface of the n-GaN layer of the epitaxial structure;
B) forming an ohmic contact metal electrode and an ohmic electrode mesa on the n + GaN layer;
C) exposing partial surface or/and side wall of the GaN sacrificial layer to obtain an exposed GaN sacrificial layer;
D) carrying out electrochemical corrosion on the exposed GaN sacrificial layer to strip the GaN-based Schottky active layer from the substrate;
E) and manufacturing a Schottky contact metal electrode to finish the manufacture of the high-frequency GaN-based thin film Schottky device.
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