A MOS transistor is manufactured. A eutectic semiconductor layer (4) of silicon and germanium is formed on a semiconductor substrate (10). The eutectic semiconductor layer (4) of silicon and germanium is doped at an impurity concentration greater than 10<20>/cm<3> by ion implantation. The doped eutectic semiconductor layer is heat-treated to form a diffused layer (5) having a low resistance and a shallow junction by solid-phase diffusion from the eutectic semiconductor layer (4). The doped eutectic semiconductor layer (4) of silicon and germanium is then removed using an etching solution to form source and drain regions.
