Wet etching preparation method of CsPbBr3 single crystal micro-groove structure

Abstract

The invention relates to a wet etching preparation method of a CsPbBr3 single crystal micro-groove structure, which comprises the following steps: taking a high-quality CsPbBr3 single crystal as a substrate, optionally selecting one surface of the CsPbBr3 single crystal as a photoetching surface, and etching the CsPbBr3 single crystal into a micron-sized micro-groove structure by adopting a photoetching mask technology and a wet etching method. The CsPbBr3 single crystal is soaked in an etching solution with a certain Ph value, after a certain period of time, a micro-groove structure with regular width and depth and with the depth changing along with the Ph value and the etching time can be formed on the surface of the CsPbBr3 single crystal, and the micro-structures are clear in outline and smooth in inner wall. According to the method, the CsPbBr3 microstructure wet etching problem is effectively solved by utilizing the selectivity characteristic of CsPbBr3 single crystal wet etching, the etching cost of the wet etching is lower, the uniformity is good, a smooth surface can be generally obtained, the method is suitable for large-area etching, and meanwhile, the method is also suitable for mass production.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a wet etching preparation method for a CsPbBr3 single crystal micro-groove structure. Background Art

[0002] In the field of semiconductor manufacturing, the etching process for micro-trench structures is a core technology, widely used in memory, logic devices, and micro-electromechanical systems. As device sizes continue to shrink and integration increases, higher requirements are placed on the etching accuracy, uniformity, and selectivity of micro-trench structures.

[0003] Especially in the emerging field of perovskite optoelectronic devices, CsPbBr3 is a semiconductor material with great potential, but the precise etching process of its micro-nano structure is still blank. At present, almost no one has been involved in the research of wet etching of CsPbBr3, which provides an important opportunity for innovation in etching technology.

[0004] In recent years, with the development of three-dimensional integrated circuits, the demand for high-aspect-ratio micro-groove structures has been increasing. Traditional etching processes face many challenges in achieving high-aspect-ratio structures, such as uneven etching rates, large sidewall roughness, and excessive bottom residues. As an ionic crystal, CsPbBr3's wet etching process must overcome unique challenges such as its solubility and difficulty in controlling anisotropy. Traditional dry etching is prone to material damage and stoichiometric imbalance. Therefore, developing a high-precision, highly selective wet etching process for CsPbBr3 will open up new avenues for micro-nanofabrication of perovskite optoelectronic devices.

[0005] This invention precisely controls a series of process parameters during the photolithography process, such as exposure and development time, and analyzes the performance of etching solutions with various pH values, ultimately developing a set of high-performance etching process flows. This breakthrough will directly promote the performance optimization and integrated development of devices such as perovskite lasers, detectors, and LEDs. Summary of the Invention

[0006] The technical problem solved by the present invention is to provide a wet etching preparation method for a CsPbBr3 single crystal micro-groove structure, so as to solve the problem of material damage caused by dry etching in the above-mentioned background technology.

[0007] The technical problem solved by the present invention is achieved by adopting the following technical solutions: A wet etching method for preparing a CsPbBr3 single crystal micro-groove structure comprises the following steps: S1. Prepare a CsPbBr3 single crystal with a (110) crystal plane as a substrate with a thickness of 800 μm; S2. Use a coating machine to spin-coat a layer of negative photoresist on one side of the CsPbBr3 single crystal, place it in a baking machine, heat it to 100°C and bake it for 60-120 seconds as a protective surface, then repeat this operation on the other side. After cooling, take it out and place it in the exposure position of the photolithography machine. Select a mask with a micro-groove pattern so that the direction of the micro-grooves on the mask is parallel to the crystal direction of the CsPbBr3 single crystal. Then, expose it for 5-20 seconds, then develop it with a developer for 5-25 seconds. After development, clean the developer, take it out and blow it dry with nitrogen to form a photolithography mask image as the photolithography surface; S3, immersing the sample in an etching solution with a Ph value of 1 to 6 for 10 to 60 minutes, etching the photoetched surface of the CsPbBr3 single crystal to form a micro-groove structure; S4. Use anhydrous acetone ultrasonic cleaning for 1 to 10 minutes to remove the photoresist.

[0008] Furthermore, the groove depth in the micro-groove structure is 1 μm to 10 μm.

[0009] Furthermore, the width of the mask groove is 10 μm to 50 μm, and the spacing between the grooves is 1:1.

[0010] Furthermore, the etching solution may be one of hydrofluoric acid solution, hydrochloric acid solution, hydrobromic acid solution, and hydroiodic acid solution, or a mixture of several of them.

[0011] Furthermore, the Ph value of the etching solution in step S3 is 3. Beneficial effects

[0012] The present invention utilizes the selective characteristics of wet etching of CsPbBr3 single crystal to effectively solve the problem of wet etching of CsPbBr3 single crystal micro-groove structure. The wet etching has lower etching cost, good uniformity, low side wall roughness, and can obtain a relatively uniform etched surface, which is suitable for large-area etching. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the structure of CsPbBr3 single crystal in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure in which one side of a CsPbBr3 single crystal is spin-coated with a negative photoresist as a protective surface in an embodiment of the present invention; Figure 3 Schematic diagram of the structure after spin coating negative photoresist on the other side of the CsPbBr3 single crystal in an embodiment of the present invention; Figure 4 A schematic structural diagram of a mask pattern in an embodiment of the present invention; Figure 5This is a schematic structural diagram of the other side of the CsPbBr3 single crystal as a photoetched surface after the negative photoresist is removed in an embodiment of the present invention; Figure 6 Schematic diagram of the etched micro-groove structure according to an embodiment of the present invention; Figure 7 Schematic diagram of the final CsPbBr3 single crystal micro-groove structure after removing the remaining photoresist in an embodiment of the present invention; Figure 8 This is the SEM image of the sample obtained by the wet etching preparation method, where the upper image is a top view and the lower image is a cross-sectional view. DETAILED DESCRIPTION

[0014] In order to make the technical means and final effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific illustrations.

[0015] Example 1: A wet etching method for preparing a CsPbBr3 single crystal micro-groove structure, comprising the following steps: S1, such as Figure 1 As shown, a CsPbBr3 single crystal with a (110) crystal plane was prepared as a substrate with a thickness of 800 μm; S2, such as Figure 2 As shown, a layer of negative photoresist is spin-coated on one side of the CsPbBr3 single crystal using a coating machine, placed in a baking machine, heated to 100 ° C and baked for 60-120 seconds as a protective surface, and then repeated this operation on the other side, as shown Figure 3 As shown; like Figure 4 and 5 As shown, after cooling, the mask is taken out and placed in the exposure position of the photolithography machine with the photolithography surface facing up. A mask with a micro-groove pattern with a groove width of 35 μm is selected so that the direction of the micro-grooves on the mask is parallel to the crystal direction of the CsPbBr3 single crystal. Then, the mask is exposed for 15 seconds and developed with a developer for 20 seconds. After development, the developer is cleaned and the mask is taken out and dried with nitrogen to form a photolithography mask image as the photolithography surface. S3, such as Figure 6 As shown, the sample was immersed in a hydrobromic acid etching solution with a Ph value of 1 for 60 minutes, and the photoetched surface of the CsPbBr3 single crystal was etched to form a micro-groove structure with a depth of 10μm and a width of 35μm. The etching rate was 166nm / min and the sidewall roughness was 40nm. S4, such as Figure 7 As shown, the photoresist was removed by ultrasonic cleaning with anhydrous acetone for 5 minutes.

[0016] Example 2-10: Compared with Example 1, the difference lies in the type of etching solution, pH value, and etching time, as shown in Table 1: Table 1: Etching parameter comparison table of Examples 1-10:

[0017] It can be seen from Examples 1 to 3 in Table 1 that as the Ph value increases, the etching rate decreases. Compared with Examples 1, 2, and 3, Examples 4 and 5 change the type of etching solution and etching time, but the results show that the type of etching solution and etching time have little effect on the etching rate and sidewall roughness. Comparing Examples 6 to 10 with Examples 1 to 3, it can be seen that the closer the Ph value is to 3, the better the sidewall roughness performance is, and the sidewall roughness is lowest when the Ph value is 3.

Claims

1. A wet etching method for preparing a CsPbBr3 single crystal micro-groove structure, characterized in that: The following steps are involved: S1. Prepare a CsPbBr3 single crystal with a (110) crystal plane as a substrate with a thickness of 800 μm; S2. Use a coating machine to spin-coat a layer of negative photoresist on one side of the CsPbBr3 single crystal, place it in a baking machine, heat it to 100°C and bake it for 60-120 seconds as a protective surface, then repeat this operation on the other side. After cooling, take it out and place it in the exposure position of the photolithography machine. Select a mask with a micro-groove pattern so that the direction of the micro-grooves on the mask is parallel to the crystal direction of the CsPbBr3 single crystal. Then, expose it for 5-20 seconds, then develop it with a developer for 5-25 seconds. After development, clean the developer, take it out and blow it dry with nitrogen to form a photolithography mask image as the photolithography surface; S3, immersing the sample in an etching solution with a Ph value of 1 to 6 for 10 to 60 minutes, etching the photoetched surface of the CsPbBr3 single crystal to form a micro-groove structure; S4. Use anhydrous acetone ultrasonic cleaning for 1 to 10 minutes to remove the photoresist.

2. The wet etching method for preparing a CsPbBr3 single crystal micro-groove structure according to claim 1, characterized in that: The groove depth in the micro-groove structure is 1 μm to 10 μm.

3. The wet etching method for preparing a CsPbBr3 single crystal micro-groove structure according to claim 1, characterized in that: The width of the mask groove is 10 μm to 50 μm, and the interval between the grooves is 1:

1.

4. The wet etching method for preparing a CsPbBr3 single crystal micro-groove structure according to claim 1, characterized in that: The etching solution may be one of hydrofluoric acid solution, hydrochloric acid solution, hydrobromic acid solution, and hydroiodic acid solution, or a mixture of several of them.

5. The wet etching method for preparing a CsPbBr3 single crystal micro-groove structure according to claim 1, characterized in that: The Ph value of the etching solution in step S3 is 3.

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