Transport of excess carriers in silicon wafers

Contactless transient photoconductivity measurements are used to study excess charge carrier transport in single-crystal silicon wafers. It is shown that the minority carrier diffusion constant and the minority carrier lifetime can be determined from the decay behaviour by varying the thickness of the wafer. The presence of non-uniform defect densities can be studied by their influence on the diffusion of excess carriers. This is demonstrated by investigation of a proton-irradiated wafer and of a wafer after an internal gettering treatmen.