High quality Ge surface passivation layer formed by thermal oxidation of Y/Ge structure

The YGeOx enjoys a low interface trap density of 2.1í 1011cm-2eV-1.Low leakage current of 3.1í 10-10A/cm2 at the effective electric field of 1MV/cm.13mV flatband voltage shift for BTI test under 10MV/cm for 8000s at 85 C. YGeOx formed by thermal oxidation of Y/Ge structure was confirmed by X-ray photoelectron spectroscopy (XPS) and its eligibility as the passivation layer for Ge MOS devices was explored in this work. Because of the thermal oxidation nature of the process that effectively suppresses dielectric structural defects and incorporates sufficient Y atoms at the interface to well passivate the dangling bonds on Ge surface; the YGeOx enjoys a small amount of oxide traps and a low interface trap density (Dit) of 2.1í 1011cm-2eV-1. In addition, the thermally grown YGeOx demonstrates a relatively high dielectric constant of 10.8 as compared to GeO2, tiny frequency dispersion in capacitance-voltage (C-V) characteristics, low leakage current of 3.1í 10-10A/cm2 at the effective electric field of 1MV/cm, 13mV flatband voltage (Vfb) shift for bias temperature instability measurement under the stress condition of 10MV/cm for 8000s at 85 C, these promising device characteristics attest to the eligibility of the YGeOx as the passivation layer for high-performance Ge MOS technology.