Screen printed c-Si thin film solar cells on insulating substrates

A simple industrially feasible process scheme, the screen printed buried base contact (BBC) concept, was applied to Cz-Si wafers as well as to c-Si thin films (CSiTF) on insulating substrates. Cells with interdigitated front grid design on untextured Cz-Si wafers show fill factors up to 73% and a maximum efficiency of 11.5%. The application of the process to CSiTF on insulating substrates yields in an V/sub oc/ of 509 mV. Despite series resistance values below 1 /spl Omega/cm/sup 2/ the cells are severely limited by a low fill factor as well as an inactive cell area of 27% including grid shading and unpassivated base area. In particular, rough surfaces of the CSiTF's prevent good printing alignment, resulting in shunt resistances below 50 /spl Omega/cm/sup 2/. These first results lead to a 3% efficiency of CSiTF cells. Thus, the challenge for future oneside contacting schemes will be the modification of the BBC concept regarding reduced alignment requirements.