Improved properties of Ge MOS capacitors with HfTiON or HfTiO gate dielectric by using wet-NO ge-surface pretreatment

Abstract

HfTiO/GeOxNy and HfTiON/GeOxNy stack gate dielectrics are prepared by using wet-NO or wet-N2O pretreatment on Ge substrate. Experimental results show that the wet NO pretreatment can lead to excellent interface properties, gate leakage properties and device reliability, especially for the HfTiON/GeOxNy dielectric. The involved mechanisms lie in the roles of N in blocking oxygen diffusion and Ge out-diffusion and suitable N incorporation in the GeO xNy interlayer, which effectively suppress further growth of GeOxNy interlayer and the growth of unstable GeO x during subsequent processing. © 2008 IEEE.