Monitoring of silicon solar cell technology via the surface photovoltage method

The surface photovoltage (SPV) technique adapted to thin samples was used to monitor solar cell technology. The relatively short minority carrier diffusion length from 70 to 80 μm found in p-bulk of the cells results from the presence of a layer with structural defects near the surface. The measurement of successively etched samples reveals that freshly cut off silicon wafers are already strongly destroyed to a depth of at least 35 μm. A diffusion length of about 300 μm was evaluated in the samples after removing the disturbed layer.