One-time wet step etching process for GaInP/GaInAs/Ge solar cell

Abstract

The invention discloses a one-time wet step etching process for a GaInP / GaInAs / Ge solar cell, which belongs to the technical field of solar cells and comprises the following steps: S1, pre-drying a wafer; S2, coating photoresist for pattern transfer on the surface of the wafer; S3, carrying out pre-baking treatment on the wafer; S4, exposing the wafer, and transferring the step pattern on the mask plate to the photoresist film; S5, preparing a potential pattern on the adhesive film through a developing technology; S6, hardening the wafer at a high temperature; S7, carrying out III V group active layer etching on the wafer in a primary wet etching solution to form a step structure; and S8, completing the whole process of one wet step etching process on the wafer through a photoresist removing and cleaning process. The process is assisted by simple, efficient and low-cost step preparation technology of photoetching, developing, etching and cleaning processes.

Description

technical field [0001] The invention belongs to the technical field of solar cells, and in particular relates to a GaInP / GaInAs / Ge solar cell primary wet step etching process. Background technique [0002] There are a large number of lattice damage defects on the sidewall of the cut surface of the GaInP / GaInAs / Ge solar cell cut by diamond grinding wheel, and the minority carrier recombination center formed by the lattice defects exposes serious edge defect leakage problems. Prepare the photolithographic mask pattern of the scribe groove by photolithography, and then etch the semiconductor active layer by dry or wet etching technology to form the step of the scribe groove (see figure 1 ), because the sidewall of the etched scribe groove is smoother than that of the grinding wheel scribing process, and the density of minority carrier recombination centers formed by lattice defects is lower, so the GaInP / GaInAs / Ge solar cells have better photoelectric conversion performance. ...

AI Technical Summary

Problems solved by technology

[0006] This process has the following disadvantages: ①The temperature of HNO3 and HBr solutions is difficult to control, the batch production operation is not easy to master, and the yield is almost uncontrollable; ②HNO3 and HBr solutions are highly corrosive to Ge substrates. The etching time and substrate thickness are not controlled correctly, and the substrate morphology is not well controlled, which will have a negative impact on the lower electrode; ③Although the buffer in the etching solution is not clearly stated, organic alcohols cannot be used in the etching solution, because There will be an esterification reaction between HNO3 and organic alcohols, so it can only be used as a buffer of glacial acetic acid. The low-temperature etching rate of this buffer is extremely low, and if it is slightly higher, it will violently smoke, which is not suitable for mass production.

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