Owing to its higher electron and hole mobilities compared to Si,Germanium(Ge)is considered as one of the promising materials in future microelectronic devices.To meet the request of high performance devices,metal/Ge Ohmic contacts with a low electron barrier height and/or a low hole barrier height are needed.However,strong Fermi-level pinning(FLP)at the vicinity of the valence band maximum of Ge results in high electron barrier height in the metal/n-Ge contacts,which leads to the degradation of Ge devices,such as Ge n-MOSFET and Ge photodetectors[1,2,3].In this study,tin(Sn)was introduced on Ge surface to prepare the thin GeSnOx by rapid thermal oxidation for modulation of Schottky barrier height in metal/n-Ge contacts.It was found that a small amount of Sn doping in Ge could effectively suppress the formation of GeOx during thermal oxidation of Ge.The absence of GeOx in the oxide interface layer significantly alleviated the Fermi-level pinning effect in n-Ge,resulting in the strong correlation between the Schottky barrier height of metal/GeSnOx/n-Ge contacts and the metal work function.This approach for reducing Schottky barrier height ofmetal/n-Ge is simple and beneficial to the advanced Ge devices.