Raman scattering and point contact current-voltage (PCIV) measurements were used as characterization tools of tin-diffused GaAs layers. Diffusion was induced by irradiating GaAs substrates covered with thin tin layers single pulses of a ruby laser. Samples processed with the lowest energies show strong damage and incomplete electrical activation as deduced from Raman and PCIV measurements, respectively. Raman microprobe in depth analysis and PCIV profiles also suggest the presence of a damaged region with incomplete electrical activation at the boundary between the molten layer and the solid substrate.