Modulation of NiGe/Ge Schottky barrier height by S and P co-introduction

The profiles and current-voltage characteristics of phosphorus (P)- and/or sulfur (S)-introduced Ge and NiGe/Ge have been investigated to clarify the mechanism of Schottky barrier height (SBH) modulation. For NiGe/nGe (NiGe/pGe), the introduction of P and the co-introduction of P and S effectively reduced (increased) SBH, which is explained by the properties of S acting as an n-type dopant with deep donor levels in Ge. In modulating the SBH, the co-introduction was the most effective. It is probably related to the fact that a higher increase in electron concentrations was observed in S and P co-introduced Ge than in P-introduced Ge.