Surface passivation of the Ge substrate by novel nitrogen plasma immersion treatment

Abstract

In this paper, a novel nitrogen plasma immersion treatment (NNPIT) with accelerating power for Ge surface passivation is presented and compared with conventional nitrogen plasma immersion treatment (NPIT). Results show that the Ge–N bond formed at a surface by NPIT can suppress the growth of Ge suboxide during high-K dielectric deposition. As for NNPIT, more nitrogen plasma drifts to the Ge surface, which is induced by the accelerating electric field, to enhance the dangling bond passivation, and thus the NNPIT method can further suppress Ge suboxide growth during high-K dielectric deposition. As a result, the C–V characteristics in terms of a flat-band voltage, hysteresis and interface state density can be significantly improved, which is promising for high performance Ge MOSFETs fabrication.