A simplified process for isotropic texturing of mc-Si

Texturing of mc-Si wafers is an important field of research currently due to the increasing amount of mc-Si used by the PV industry. Different techniques are under investigation. One of the most promising techniques is isotropic etching with HF, HNO/sub 3/ and organic additives. We have found an etch consisting of only HF and HNO/sub 3/ that leads to comparable improvements in reflection and I-V characteristics, but is easier to handle and less critical during the etch process. The wafers can be etched horizontally compatible with existing in-line etch systems and the etch depth is only 5 /spl mu/m from the as-cut wafer, which is beneficial for thin wafers. It is suitable not only for block-cast Si but with some adaptation also for EFG, SR, Tri-Si, and RGS. A relative efficiency gain of 7% on cell level and 4.8% with a 36 cell module has been reached.