Suppressing the formation of GeOx by doping Sn into Ge to modulate the Schottky barrier height of metal/n-Ge contact

Tin (Sn) was introduced into Ge for the preparation of a thin GeSnOx by thermal oxidation, which could strongly modulate the Schottky barrier height of metal/n-Ge contacts. A small amount of Sn doping in Ge could effectively suppress the formation of GeOx during oxidation, alleviating the Fermi-level pinning effect in Ge. This resulted in the strong correlation between the Schottky barrier heights of metal/GeSnOx/n-Ge contacts and metal work functions. The ohmic Al/n-Ge contacts and the extremely low leakage current density of the HfO2/Ge structure achieved by the simple thermal oxidation of a Sn-doped Ge surface suggested the potential of this method in the fabrication of Ge-based devices. (C) 2016 The Japan Society of Applied Physics