Interpretation of minority carrier diffusion length measurements in thin silicon wafers

Diffusion length of minority carriers measured in thin wafers reflects not only properties of the material but also the state of its surface and, consequently, becomes an effective quantity Leff depending on the thickness of the sample. The function describing this dependence is presented here and compared with the data from surface photovoltage experiments. It allows one to find the correct diffusion length from measurement of two samples with different thicknesses.