An Optical Technique for Measuring Surface Recombination Velocity

The surface recombination velocity is a critical parameter in silicon device applications including solar cells. In this work, we developed and applied a contactless optical/radio-frequency technique to provide quick, contactless measurement of the surface recombination velocity. The basic technique is to probe the excess carrier lifetime in the surface and bulk regions of a semiconductor wafer by varying the excitation wavelength. Here, we have derived a theoretical functional model that describes the experimental photoconductive transient. A curve fitting procedure provides a determination for both the bulk recombination lifetime and the surface recombination velocity.