Minority carrier lifetime in plasma-textured silicon wafers for solar cells

In this work a comparison between plasma induced defects by two different SF6 etching techniques, Reactive Ion Etching (RIE) and High density Plasma (HDP), is presented. It is found that without any Defect Remove Etching (DRE), the minority carrier lifetime is the highest for the HDP technique. After DRE, the minority carrier lifetime rises as high as 750 μs for both RIE and HDP textured wafers at an excess carrier density of 1x10 15 cm -3 . The measured lifetimes correspond to an implied one-sun opencircuit voltage of around 680mV compared to about 640mV before DRE for the HDP textured wafers. We also noted that in the RIE process the induced defect density was significantly lower for wafers etched at 300 K than those etched at 173 K.