A gallium arsenide cell epitaxial structure and a method of fabricating the same

Abstract

The application provides a gallium arsenide battery epitaxial structure and a preparation method thereof. The gallium arsenide battery epitaxial structure comprises a substrate, a sacrificial layer and a battery layer arranged on the substrate, the sacrificial layer and the battery layer are sequentially stacked in a direction away from the substrate, the sacrificial layer can be separated from the battery layer by wet etching assisted substrate, and the thickness of the sacrificial layer gradually decreases from an edge region to a central region. The gallium arsenide battery epitaxial structure has a sacrificial layer structure design, which is helpful for the etching liquid to flow from the edge region of the sacrificial layer to the central region after the edge region is etched, thereby accelerating the overall etching rate of the sacrificial layer, and at the same time, the bending degree of the battery layer can be relatively reduced to a certain extent after the edge region of the sacrificial layer is etched by the etching liquid, thereby reducing the possibility of the closed formation of the bent battery layer and the substrate to a certain extent, the etching liquid can quickly etch the middle region of the sacrificial layer, and the peeling efficiency of the substrate is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a gallium arsenide cell epitaxial structure and a preparation method thereof. BACKGROUND

[0002] Gallium arsenide (GaAs) is one of the most optimal materials for absorbing sunlight. The solar cell prepared from gallium arsenide has the characteristics of high conversion efficiency, good temperature characteristics, strong anti-radiation ability, etc. and is increasingly widely used.

[0003] Most gallium arsenide thin films are prepared on expensive single crystal substrates, which is high in cost. The substrate stripping technology provides necessary technical support for the development of solar cells to thin films. The repeated use of the substrate also reduces the manufacturing cost of thin film solar cells and reduces environmental pollution and resource waste in the manufacturing process.

[0004] Generally, a sacrificial layer with a thickness of about 100 nm is grown between the substrate and the cell layer, and then the substrate is stripped by using a wet acid etching process. The etching process proceeds from the periphery of the cell to the center, which not only requires a long etching time, but also the position of the sacrificial layer around which is etched off is easy to form a closed loop with the substrate due to the bending of the cell layer, so that the etching liquid is difficult to further etch the center of the sacrificial layer. The sacrificial layer at the center position is often not completely etched, which easily causes the cell layer to be torn by the pulling force during the substrate stripping process. SUMMARY

[0005] The present application provides a gallium arsenide cell epitaxial structure and a preparation method thereof to solve the above technical problems in the prior art. The gallium arsenide cell epitaxial structure has a sacrificial layer with a thickness gradually decreasing from the edge region to the center region. In the process of stripping the substrate by wet etching, the etching liquid can flow from the edge region to the center region of the sacrificial layer after etching the edge region, thereby accelerating the overall etching rate of the sacrificial layer. At the same time, the structural design of the sacrificial layer can relatively reduce the bending degree of the cell layer to a certain extent after the edge region of the sacrificial layer is etched off by the etching liquid, thereby reducing the possibility of the closed loop formed by the bent cell layer and the substrate to a certain extent, which is helpful for the etching liquid to quickly etch the middle region of the sacrificial layer, thereby improving the stripping efficiency of the substrate.

[0006] The present application provides a gallium arsenide cell epitaxial structure, which comprises a substrate, a sacrificial layer and a cell layer arranged on the substrate. The sacrificial layer and the cell layer are sequentially stacked in the direction away from the substrate. The sacrificial layer can assist the separation of the substrate and the cell layer by wet etching. The thickness of the sacrificial layer gradually decreases from the edge region to the center region.

[0007] Preferably, the thickness difference of the edge region and the center region of the sacrificial layer ranges from 10 to 50 nm.

[0008] Preferably, one side of the sacrificial layer away from the substrate is a concave arc surface recessed towards the substrate side, and the other side of the sacrificial layer close to the substrate is a concave arc surface recessed towards the battery layer side.

[0009] Preferably, one side of the sacrificial layer away from the substrate is a concave arc surface recessed towards the substrate side, and the other side of the sacrificial layer close to the substrate is a plane.

[0010] Preferably, one side of the sacrificial layer away from the substrate is a plane, and the other side of the sacrificial layer close to the substrate is a concave arc surface recessed towards the battery layer side.

[0011] Preferably, a buffer layer is further included, which is arranged between the substrate and the sacrificial layer, and one side of the buffer layer away from the substrate is a convex arc surface protruding towards the sacrificial layer side, and the convex arc surface of the buffer layer is in conformity with the concave arc surface of the sacrificial layer.

[0012] Preferably, a warping adjustment layer and an ohmic contact layer are further included, which are arranged between the sacrificial layer and the battery layer, and in the direction away from the sacrificial layer, the ohmic contact layer and the warping adjustment layer are sequentially stacked, and the surface of the warping adjustment layer in contact with the battery layer is a plane.

[0013] Preferably, the warping adjustment layer adopts Al InP or AlGaAs material.

[0014] The application further provides a preparation method of the above gallium arsenide battery epitaxial structure, which comprises sequentially preparing a sacrificial layer and a battery layer on a substrate, and when the sacrificial layer is prepared, the temperature for forming the sacrificial layer in the process environment is gradually reduced from the center region of the sacrificial layer to the edge region of the sacrificial layer.

[0015] Preferably, the temperature difference for forming the center region of the sacrificial layer and the temperature for forming the edge region of the sacrificial layer ranges from 50 to 100 ℃.

[0016] Preferably, the preparation method further comprises preparing a buffer layer, and adjusting the temperature for forming the buffer layer in the process environment to be gradually increased from the center region of the buffer layer to the edge region of the buffer layer.

[0017] Preferably, the temperature difference for forming the edge region of the buffer layer and the temperature for forming the center region of the buffer layer ranges from 50 to 100 ℃.

[0018] Preferably, the preparation method further comprises: successively preparing the ohmic contact layer and the warpage adjustment layer, and forming the warpage adjustment layer comprises: adjusting the content of the aluminum component in the warpage adjustment layer material and / or adjusting the thickness of the warpage adjustment layer in the process of forming the warpage adjustment layer, so that the surface of the formed warpage adjustment layer in contact with the battery layer is a plane.

[0019] The gallium arsenide battery epitaxial structure provided by the present application has the following beneficial effects: the sacrificial layer with gradually decreasing thickness from the edge region to the center region is arranged, which is helpful for the etching liquid to flow from the edge region to the center region of the sacrificial layer after the etching liquid corrodes the edge region of the sacrificial layer, so that the overall etching rate of the sacrificial layer can be accelerated, meanwhile, the structure design of the sacrificial layer can relatively reduce the bending degree of the battery layer to a certain extent after the edge region of the sacrificial layer is corroded by the etching liquid, so that the possibility of the closed formation of the bent battery layer and the substrate is reduced to a certain extent, the etching liquid can quickly corrode the middle region of the sacrificial layer, and the peeling efficiency of the substrate is improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 FIG. 1 is a structural cross-sectional view of a gallium arsenide battery epitaxial structure according to an embodiment of the present application;

[0021] Figure 2 FIG. 2 is a structural cross-sectional view of another gallium arsenide battery epitaxial structure according to an embodiment of the present application;

[0022] Figure 3 FIG. 3 is a structural cross-sectional view of another gallium arsenide battery epitaxial structure according to an embodiment of the present application.

[0023] The reference signs in the drawings are explained as follows:

[0024] 1. substrate; 2. sacrificial layer; 3. battery layer; 4. buffer layer; 5. warpage adjustment layer; 6. ohmic contact layer. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions of the present application, the gallium arsenide battery epitaxial structure and the preparation method thereof provided by the present application are further described in detail below in combination with the drawings and specific embodiments.

[0026] In order to solve the technical problem that the existing gallium arsenide battery substrate peeling leads to battery failure, the present embodiment provides a gallium arsenide battery epitaxial structure, as shown in FIG. 1, which comprises a substrate 1 and a sacrificial layer 2 and a battery layer 3 arranged on the substrate 1, the sacrificial layer 2 and the battery layer 3 are sequentially stacked in the direction away from the substrate 1, the sacrificial layer 2 can be separated from the battery layer 3 by wet etching, and the thickness of the sacrificial layer 2 gradually decreases from the edge region to the center region. Figure 1 The gallium arsenide battery epitaxial structure provided by the present application has the following beneficial effects: the sacrificial layer with gradually decreasing thickness from the edge region to the center region is arranged, which is helpful for the etching liquid to flow from the edge region to the center region of the sacrificial layer after the etching liquid corrodes the edge region of the sacrificial layer, so that the overall etching rate of the sacrificial layer can be accelerated, meanwhile, the structure design of the sacrificial layer can relatively reduce the bending degree of the battery layer to a certain extent after the edge region of the sacrificial layer is corroded by the etching liquid, so that the possibility of the closed formation of the bent battery layer and the substrate is reduced to a certain extent, the etching liquid can quickly corrode the middle region of the sacrificial layer, and the peeling efficiency of the substrate is improved.

[0027] The above thickness of the sacrificial layer 2 is helpful for the etching liquid to flow from the edge region to the center region of the sacrificial layer 2 after the etching liquid etches the edge region of the sacrificial layer 2, so as to accelerate the etching rate of the whole sacrificial layer 2 and improve the peeling efficiency of the substrate 1. Meanwhile, the edge region of the sacrificial layer 2 is thicker, so that the corresponding edge region of the battery layer 3 is warped away from the substrate 1. If the warping degree of the edge region of the battery layer 3 does not change after the edge region of the sacrificial layer 2 is etched away, the warped edge region of the battery layer 3 and the substrate 1 cannot form a closed loop. Therefore, the structure of the sacrificial layer 2 can relatively reduce the warping degree of the battery layer 3 to some extent, so as to reduce the possibility of the warped battery layer 3 and the substrate 1 forming a closed loop to some extent, and then help the etching liquid to quickly etch the middle region of the sacrificial layer 2 and improve the peeling efficiency of the substrate 1.

[0028] Preferably, the thickness difference between the edge region and the center region of the sacrificial layer 2 is 10-50 nm. The thickness difference is more helpful for reducing the possibility of the warped battery layer 3 and the substrate 1 forming a closed loop to some extent, so as to help the etching liquid to quickly etch the middle region of the sacrificial layer 2 and improve the peeling efficiency of the substrate 1.

[0029] In the embodiment, the side of the sacrificial layer 2 away from the substrate 1 is a concave arc surface recessed toward the substrate 1, and the side of the sacrificial layer 2 close to the substrate 1 is a concave arc surface recessed toward the battery layer 3. That is, the cross-sectional shape of the sacrificial layer 2 is dumbbell-shaped along the cross section perpendicular to the substrate 1. The dumbbell-shaped sacrificial layer 2 is more helpful for the etching liquid to flow from the edge region to the center region of the sacrificial layer 2 after the etching liquid etches the edge region of the sacrificial layer 2, so as to further accelerate the etching rate of the whole sacrificial layer 2 and further improve the peeling efficiency of the substrate 1.

[0030] In the embodiment, the substrate 1 is a gallium arsenide (GaAs) substrate, a germanium (Ge) substrate or a silicon carbide (SiC) substrate, but is not limited to the above-mentioned substrate 1. The sacrificial layer 2 is made of aluminum arsenide (AlAs) material, and the aluminum arsenide sacrificial layer 2 can be removed by acid wet etching liquid. The thickness of the sacrificial layer 2 is 10-150 nm.

[0031] In the embodiment, the gallium arsenide battery epitaxial structure further comprises a buffer layer 4, which is arranged between the substrate 1 and the sacrificial layer 2. The side of the buffer layer 4 away from the substrate 1 is a convex arc surface protruding toward the sacrificial layer 2, and the convex arc surface of the buffer layer 4 is in close contact with the concave arc surface of the sacrificial layer 2. That is, in order to realize the above structure of the sacrificial layer 2, the buffer layer 4 in the embodiment is arranged to have a structure of a thicker middle region and a thinner edge region, and the thickness difference between the middle region and the edge region of the buffer layer 4 is 10-50 nm.

[0032] The buffer layer 4 is made of gallium arsenide (GaAs) material, and has a thickness ranging from 100 to 1000 nm.

[0033] Preferably, in the embodiment, the gallium arsenide cell epitaxial structure further comprises a warpage adjustment layer 5 and an ohmic contact layer 6, the ohmic contact layer 6 and the warpage adjustment layer 5 are arranged between the sacrificial layer 2 and the cell layer 3, and the ohmic contact layer 6 and the warpage adjustment layer 5 are sequentially stacked in a direction away from the sacrificial layer 2, and a surface of the warpage adjustment layer 5 in contact with the cell layer 3 is a plane. The surface of the warpage adjustment layer 5 in contact with the cell layer 3 is a plane, so that the cell layer 3 prepared on the warpage adjustment layer 5 tends to be flat, thereby avoiding the influence of the sacrificial layer 2 with a dumbbell-shaped cross section on the preparation of the cell layer 3, and the flatness of the cell layer 3 also ensures the stability of photoelectric conversion of the entire gallium arsenide cell epitaxial structure.

[0034] The warpage adjustment layer 5 is made of AlInP or AlGaAs material. The ohmic contact layer 6 is n-type heavily doped GaAs, with a doping concentration of 1×1018cm-3 and a thickness of 100-200 nm. In addition, the cell layer 3 comprises a BSF layer (back surface field layer), a base layer, an emitter layer, a window layer, a P-type ohmic contact layer, and the like, which are sequentially stacked away from the sacrificial layer 2, and the cell layer 3 is a single-junction or a multi-junction gallium arsenide cell epitaxial structure composed of a single-junction sub-cell and a tunnel junction. 18 cm -3 -1×10 22 cm -3 , thickness 100-200 nm. In addition, the cell layer 3 comprises a BSF layer (back surface field layer), a base layer, an emitter layer, a window layer, a P-type ohmic contact layer, and the like, which are sequentially stacked away from the sacrificial layer 2, and the cell layer 3 is a single-junction or a multi-junction gallium arsenide cell epitaxial structure composed of a single-junction sub-cell and a tunnel junction.

[0035] Based on the above structure of the gallium arsenide cell epitaxial structure, the embodiment further provides a preparation method of the gallium arsenide cell epitaxial structure, which comprises sequentially preparing a sacrificial layer and a cell layer on a substrate. When the sacrificial layer is prepared, the temperature for forming the sacrificial layer in the process environment is gradually reduced from the center region of the sacrificial layer to the edge region of the sacrificial layer.

[0036] By adjusting the temperature for forming the sacrificial layer to gradually decrease from the center region to the edge region, the preparation rate of the center region of the sacrificial layer is adjusted to be lower than that of the edge region, so that the preparation rate of the center region is lower than 2 μm / h, the preparation rate of the edge region is higher than that of the center region and lower than 3 μm / h, and finally a sacrificial layer with a thickness of the edge region higher than that of the center region is prepared.

[0037] Preferably, the temperature difference between the center region of the sacrificial layer and the edge region of the sacrificial layer ranges from 50 to 100 ℃. The temperature in the process environment for preparing the sacrificial layer ranges from 600 to 1000 ℃, and the preparation time ranges from 10 to 300 s.

[0038] In the embodiment, the preparation method further comprises: preparing the buffer layer, and adjusting the temperature for forming the buffer layer in the process environment to gradually increase from the central region of the buffer layer to the edge region of the buffer layer.

[0039] By adjusting the temperature for forming the edge region of the buffer layer to gradually decrease to the central region, the preparation rate of the edge region of the buffer layer can be adjusted to be lower than that of the central region, the preparation rate of the edge region is lower than 2 μm / h, the preparation rate of the central region is higher than that of the edge region and lower than 3 μm / h, and finally the buffer layer with the central region having a thickness higher than that of the edge region is prepared.

[0040] Preferably, the temperature difference between the central region of the buffer layer and the edge region of the buffer layer ranges from 50 to 100 ℃. The temperature in the process environment for preparing the buffer layer ranges from 600 to 1000 ℃, and the preparation time ranges from 10 to 500 s.

[0041] The preparation method further comprises: preparing the ohmic contact layer and the warpage adjustment layer in sequence, and the forming of the warpage adjustment layer comprises: adjusting the content of the aluminum component in the warpage adjustment layer material during the forming of the warpage adjustment layer, and adjusting the thickness of the warpage adjustment layer, so that the surface of the formed warpage adjustment layer in contact with the battery layer is a plane.

[0042] Specifically, the less the content of the aluminum component and the thinner the thickness, the smaller the concavity of the surface of the warpage adjustment layer in contact with the battery layer; and vice versa, the more the content of the aluminum component and the thicker the thickness, the greater the concavity of the surface of the warpage adjustment layer in contact with the battery layer.

[0043] Of course, only one of the aluminum component and the thickness of the warpage adjustment layer can be adjusted. The preparation temperature of the warpage adjustment layer ranges from 400 to 1000 ℃. The preparation temperature of the ohmic contact layer ranges from 600 to 1000 ℃.

[0044] In addition, it should be noted that each film layer in the preparation of the buffer layer, the sacrificial layer, the ohmic contact layer, the warpage adjustment layer and the battery layer is prepared by using the traditional and mature metal organic chemical vapor deposition method, molecular beam epitaxy method, vapor phase epitaxy method or physical vapor deposition method, and details are not described herein.

[0045] Different from the above embodiment, the present embodiment provides a gallium arsenide battery epitaxial structure, as shown in Figure 2 The surface of the sacrificial layer 2 away from the substrate 1 is a concave arc surface recessed to the substrate 1 side, and the surface of the sacrificial layer 2 close to the substrate 1 is a plane.

[0046] In this way, in the process of stripping the substrate 1 by wet etching, the etching liquid also flows from the edge region of the sacrificial layer 2 to the central region, so as to accelerate the etching rate of the sacrificial layer 2 as a whole, thereby improving the stripping efficiency of the substrate 1. In addition, due to the thicker edge region of the sacrificial layer 2, the corresponding edge region of the battery layer 3 is warped away from the substrate 1. If the warping degree of the edge region of the battery layer 3 does not change after the edge region of the sacrificial layer 2 is etched away, the warped edge region of the battery layer 3 cannot form a closed loop with the substrate 1. Therefore, the structure of the sacrificial layer 2 can reduce the warping degree of the battery layer 3 to some extent, thereby reducing the possibility of forming a closed loop between the warped battery layer 3 and the substrate 1, and further facilitating the rapid etching of the central region of the sacrificial layer 2 by the etching liquid, thereby improving the stripping efficiency of the substrate 1.

[0047] In this embodiment, the buffer layer 4 is also arranged between the substrate 1 and the sacrificial layer 2. However, different from the above-mentioned embodiments, since the surface of the sacrificial layer 2 close to the substrate 1 is a plane, the buffer layer 4 is a film layer with a constant thickness, and the surface of the buffer layer 4 close to the substrate 1 and the surface of the buffer layer 4 away from the substrate 1 are both planes.

[0048] In this embodiment, the other structures of the gallium arsenide battery epitaxial structure are the same as those in the above-mentioned embodiments, which will not be described here.

[0049] Based on the above-mentioned structure of the gallium arsenide battery epitaxial structure, this embodiment further provides a preparation method of the gallium arsenide battery epitaxial structure. Different from the preparation method in the above-mentioned embodiments, the buffer layer does not need to be adjusted in the preparation process to achieve different thicknesses in different regions.

[0050] The other steps of the preparation method of the gallium arsenide battery epitaxial structure in this embodiment are the same as those in the above-mentioned embodiments, which will not be described here.

[0051] Different from the above-mentioned two embodiments, this embodiment provides a gallium arsenide battery epitaxial structure, as shown in Figure 3 The surface of the sacrificial layer 2 away from the substrate 1 is a plane, and the surface of the sacrificial layer 2 close to the substrate 1 is a concave arc surface recessed toward the battery layer 3.

[0052] Thus, in the process of stripping the substrate 1 by wet etching, the etching liquid can flow from the edge region to the center region of the sacrificial layer 2 after etching the edge region, so as to accelerate the overall etching rate of the sacrificial layer 2, and thus improve the stripping efficiency of the substrate 1. In addition, due to the relatively increased distance between the edge region of the battery layer 3 and the substrate 1, if the bending degree of the edge region of the battery layer 3 does not change after the edge region of the sacrificial layer 2 is etched, the edge region of the battery layer 3 cannot form a closed loop with the substrate 1, so the structure of the sacrificial layer 2 can reduce the bending degree of the battery layer 3 to a certain extent, so as to reduce the possibility of the closed loop of the battery layer 3 and the substrate 1, and thus facilitate the etching liquid to quickly etch the middle region of the sacrificial layer 2, and improve the stripping efficiency of the substrate 1.

[0053] In the embodiment, the structure of the buffer layer 4 is the same as that in the first embodiment.

[0054] In addition, in the embodiment, the surface of the sacrificial layer 2 away from the substrate 1 is flat, which does not affect the preparation of the battery layer 3 with photoelectric conversion stability on the sacrificial layer 2, so the warping adjustment layer does not need to be arranged. In the embodiment, the warping adjustment layer is not arranged.

[0055] In the embodiment, the other structures of the gallium arsenide battery epitaxial structure are the same as those in the first embodiment, which will not be described here.

[0056] Based on the structure of the gallium arsenide battery epitaxial structure, the embodiment further provides a preparation method of the gallium arsenide battery epitaxial structure. Different from the preparation methods in the above two embodiments, the warping adjustment layer does not need to be prepared in the embodiment.

[0057] In the embodiment, the other steps of the preparation method of the gallium arsenide battery epitaxial structure are the same as those in the first embodiment, which will not be described here.

[0058] The gallium arsenide battery epitaxial structure provided by the application has the following beneficial effects. By arranging the sacrificial layer with the thickness gradually decreasing from the edge region to the center region, in the process of stripping the substrate by wet etching, the etching liquid can flow from the edge region to the center region of the sacrificial layer after etching the edge region, so as to accelerate the overall etching rate of the sacrificial layer. In addition, the structure of the sacrificial layer can reduce the bending degree of the battery layer to a certain extent after the edge region of the sacrificial layer is etched by the etching liquid, so as to reduce the possibility of the closed loop of the battery layer and the substrate to a certain extent, and thus facilitate the etching liquid to quickly etch the middle region of the sacrificial layer, and improve the stripping efficiency of the substrate.

[0059] It is understood that the above embodiments are only exemplary for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and scope of the present application, and these modifications and improvements are also considered as the protection scope of the present application.

Claims

1. A gallium arsenide cell epitaxial structure comprising a substrate and a sacrificial layer and a cell layer disposed on the substrate, the sacrificial layer and the cell layer being stacked in order in a direction away from the substrate, the sacrificial layer being capable of assisting separation of the substrate from the cell layer by wet etching, characterized in that, The thickness of the sacrificial layer gradually decreases from the edge region to the center region; The thickness difference between the edge region and the center region of the sacrificial layer ranges from 10 to 50 nm; The gallium arsenide cell epitaxial structure further comprises a warping adjustment layer and an ohmic contact layer, the ohmic contact layer and the warping adjustment layer are arranged between the sacrificial layer and the cell layer, and the ohmic contact layer and the warping adjustment layer are sequentially stacked in a direction away from the sacrificial layer, and the surface of the warping adjustment layer in contact with the cell layer is a plane; The warping adjustment layer is made of AlInP or AlGaAs material.

2. The gallium arsenide cell epitaxial structure of claim 1, wherein, The surface of the sacrificial layer away from the substrate is a concave arc surface recessed toward the substrate side, and the surface of the sacrificial layer close to the substrate is a concave arc surface recessed toward the cell layer side.

3. The gallium arsenide cell epitaxial structure of claim 1, wherein, The surface of the sacrificial layer away from the substrate is a concave arc surface recessed toward the substrate side, and the surface of the sacrificial layer close to the substrate is a plane.

4. The gallium arsenide cell epitaxial structure of claim 1, wherein, The surface of the sacrificial layer away from the substrate is a plane, and the surface of the sacrificial layer close to the substrate is a concave arc surface recessed toward the cell layer side.

5. A gallium arsenide cell epitaxial structure according to claim 2 or 4, wherein, Further comprising a buffer layer arranged between the substrate and the sacrificial layer, and the surface of the buffer layer away from the substrate is a convex arc surface protruding toward the sacrificial layer side, and the convex arc surface of the buffer layer is matched with the concave arc surface of the sacrificial layer.

6. A method of producing a gallium arsenide cell epitaxial structure as claimed in any one of claims 1 to 5, comprising successively producing a sacrificial layer and a cell layer on a substrate, characterized in that, When preparing the sacrificial layer, the temperature for forming the sacrificial layer in the process environment is gradually reduced from the center region of the sacrificial layer to the edge region of the sacrificial layer.

7. The production method according to claim 6, wherein The gallium arsenide cell epitaxial structure is the gallium arsenide cell epitaxial structure of claim 5, and the preparation method further comprises: preparing a buffer layer, and adjusting the temperature for forming the buffer layer in the process environment to gradually increase from the center region of the buffer layer to the edge region of the buffer layer.

8. The method of claim 7, wherein, The temperature difference between the center region of the sacrificial layer and the edge region of the sacrificial layer, and / or the temperature difference between the edge region of the buffer layer and the center region of the buffer layer ranges from 50 to 100℃.

9. The preparation method according to claim 6, characterized in that, The gallium arsenide cell epitaxial structure is the gallium arsenide cell epitaxial structure of claim 1, and the preparation method further comprises: preparing an ohmic contact layer and a warping adjustment layer in sequence, and forming the warping adjustment layer comprises: adjusting the content of aluminum component in the material of the warping adjustment layer and / or adjusting the thickness of the warping adjustment layer during the formation of the warping adjustment layer, so that the surface of the formed warping adjustment layer in contact with the cell layer is a plane.

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