An improved method is described for extracting material parameters from an experimental electron-beam-induced current ~EBIC! contrast profile across a vertical grain boundary by directly fitting an analytical expression. This allows the least-squares values of the grain boundary recombination velocity and the diffusion length in each grain to be determined without the need for the reduction of the experimental profile to a few integral parameters, as is required in a previously reported method. Greater accuracy of the extracted values is expected since none of the information contained in the experimental contrast data is discarded and a less extensive spatial range of measured data is required than in the commonly used method. Different models of the carrier generation volume are used in the fitting and the effect of the choice of generation model on extracted values is investigated. In common with other EBIC approaches, this method is insensitive to changes in the diffusion length when the collection efficiency is high and diffusion lengths may not be reliably established in those cases.