Wide range control of Schottky barrier heights at metal/Ge interfaces with nitrogen-contained amorphous interlayers formed during ZrN sputter deposition

A ZrN contact on a Ge substrate can alleviate the intrinsic Fermi-level pinning (FLP) position toward conduction band edge, which is induced by an amorphous interlayer (a-IL) containing nitrogen atoms at the interfaces. Since the a-IL could be retained on the Ge surface, we demonstrated a wide range Schottky barrier height (SBH) control for metal/a-IL/Ge contacts. The sputtering power for ZrN affects the SBH, pinning factor (S), and effective charge neutral level. A high S value of 0.26 was achieved, which is comparable to that of metal/Si contacts. A model was proposed for explaining the mechanism of this effective FLP alleviation.