Improved spatial resolution diffusion length measurements in imperfect silicon

The Electron Beam Induced Current (EBIC) method for measuring the minority carrier diffusion length L in semiconductors has been modified to allow for a significant improvement in spatial resolution along the surface of the sample. With this modification, L at a particular point can be determined with spatial resolution close to the limit determined by the electron beam spreading in the semiconductor. The method is particularly suitable for imperfect silicon with L on the order of 50 μm, that is, for silicon often used for solar cells. The use of the method for silicon ribbon which contains dislocations and grain boundaries is illustrated.