Two-step texture process for high-efficiency crystalline silicon solar cell applications.

Anisotropic etching of single-crystalline solar cells is used to increase the light absorption and surface area, which can improve the conversion efficiency. However, the conventional anisotropic etching process is limited for increasing surface area. For high-efficiency solar cells, unique surface structures are necessary. We present a new two-step texture process that involves combining dry etching and wet etching to produce a high-aspect-ratio surface structure for high-efficiency solar cells. Using this process, we achieved pillar-type surface structure with 1:1.9 aspect ratios in reactive ion etching (RIE), and the aspect ratio was increased further to 1:2.6 by the anisotropic wet etching process. The reflectance of the c-Si wafer was reduced from 24% to 12% by this two-step texturing process. This new technique can be used to increase the aspect ratio and surface area for high-efficiency c-Si solar cells.