Texturing of multi-crystalline silicon using isotropic etching solution

Surface Texturing is very important process for high cell efficiency in crystalline silicon solar cell. Anisotropic texturing with an alkali etchant was known not to be able to produce uniform surface morphology in multi-crystalline silicon (mc-Si), because of its different etching rate with random crystal orientation. In order to reduce surface reflectance of mc-Si wafer, the general etching tendency was studied with HF/HNO₃/De-ionized Water acidic solution. And the surface structures of textured mc-Si in various HF/ HNO ₃ ratios were compared. The surface morphology and reflectance of textured silicon wafers were measured by FE-SEM and UVvisible spectrophotometer, respectively. We obtained average reflectance of 16∼19% for wavelength between 400 nm and 900 nm depending on different etching conditions.