Effects of postgate dielectric treatment on germanium-based metal-oxide-semiconductor device by supercritical fluid technology

摘要

Supercritical fluid (SCF) technology is employed at low temperature as a postgate dielectric treatment to improve gate SiO2∕germanium (Ge) interface in a Ge-based metal-oxide-semiconductor (Ge-MOS) device. The SCF can transport the oxidant and penetrate the gate oxide layer for the oxidation of SiO2∕Ge interface at 150 °C. A smooth interfacial GeO2 layer between gate SiO2 and Ge is thereby formed after SCF treatment, and the frequency dispersion of capacitance-voltage characteristics is also effectively alleviated. Furthermore, the electrical degradation of Ge-MOS after a postgate dielectric annealing at 450 °C can be restored to a extent similar to the initial state.