Hydrazine-Based Fermi-Level Depinning Process on Metal/Germanium Schottky Junction

In this letter, we propose a hydrazine (N₂H₄)-based nitridation process, which reduces the native oxide (GeO_x) component and finally transforms it into GeO_xN_y on intrinsic Ge, to relieve the E_F pinning problem. The decomposition of GeO_x and formation of GeO_xN_y by N₂H₄ are systematically investigated through cross-sectional transmission electron microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy analyses. After performing the N₂H₄-based nitridation process for 12 h, high Φ_H (~0.59 eV) and therefore high ON/OFF current ratio (~10⁴) are achieved for Ti/Ge Schottky junction diode.