The electrical and material properties of HfO xN y dielectric on germanium substrate

Abstract

Hafnium oxynitride (HfO xN y) film was investigated as a possible gate dielectric of germanium metal-oxide-semiconductor (MOS) device. The thin HfO xN y dielectric was prepared using reactive sputtering, followed by post deposition annealing (PDA). The dependence of the equivalent oxide thickness (EOT) on PDA condition was investigated. A small EOT of 19.7 Å with a low leakage current of 3.1 × 10 -5 A/cm 2 (V g = 1 V) was achieved with PDA at 600°C. In addition, the material properties of HfO xN y on germanium were analyzed by X-ray photoelectron spectroscopy. The nitrogen is found to pile up at the dielectric/substrate interface and to form Ge-N bonds, which contribute to the interfacial layer (IL) suppression.