Pure germanium nitride formation by atomic nitrogen radicals for application to Ge metal-insulator-semiconductor structures

摘要

We have investigated the nitridation of germanium using atomic nitrogen radicals generated by a remote rf plasma source. Pure amorphous Ge_3N_4 films without oxygen are obtained by the direct nitridation of clean Ge substrates. The conformal growth with smooth surface and sharp interface can be achieved in the Ge_3N_4 films grown at 100℃, where the maximum thickness of the Ge_3N_4 films is approximately 3 nm. While the surfaces of the Ge_3N_4 films are partially oxidized by the exposure to air, the Ge_3N_4 films exhibit the high resistance against oxygen diffusion. The Ge_3N_4 films are water insoluble and soluble in HF. These results demonstrate that pure direct nitridation of Ge substrates has a possibility to be used not only as a passivation layer but also as a diffusion barrier layer against oxygen for Ge metal-insulator-semiconductor field effect transistor applications.