n** plus -Si has been found to be an ohmic contact to n-GaAs. The n** plus -Si films were formed on n-GaAs by conventional vacuum evaporation and P** plus ion implantation. Even after annealing at 850 degree C, the surface and the interface of the n** plus -Si/n-GaAs structure were uniform and ohmic contact characteristics were observed. By using Al as electrodes on the n** plus -Si film, the contact resistivity of about 1. 5 OMEGA multiplied by (times) mm was obtained, which was only three times higher than that of the conventional Au-Ge alloyed contact. MESFETs were fabricated and the Al/n** plus -Si contact to n-GaAs was found to be stable at least up to 500 degree C.