Wet/dry etching combined microtextured structures for high‐efficiency solar cells

Abstract

A solar cell texturing process using a two-step process that includes wet etching and dry etching has been developed. The surface reflectance and fill factor (FF) of the pyramid structure by general wet etching texturing process were 5.834 and 70.597%, respectively; the surface reflectance and FF of the two-step pyramid structure by wet etching and dry etching texturing process were 3.69 and 65.013%; and the surface reflectance and FF of the two-step pyramid structure by rounded pyramid and dry etching texturing process were 4.533 and 70.727%. The process of the two-step pyramid structure is as follows. First, the pyramid structure formed by the wet etching process was etched again with tetramethylammonium hydroxide solution. Then, the crest and the trough of the pyramid structure was fine etched, and rounded pyramid structures with a uniform n+ layer was formed. Secondly, a pyramid structure with a high angle on the rounded pyramid structure was formed by using reactive-ion etching with a metal mesh. The two-step pyramid structure by the wet etching and dry etching texturing process has a lower surface reflectance and higher FF than the pyramid structure formed of the wet etching texturing process. Therefore, the etching process is suitable for producing high-efficiency solar cells.