Impact of N_2O/NH_3/N_2 Gas Mixture on the Interface Quality of Germanium MOS Capacitors

摘要

In this paper, nitration of germanium surface using a mixture of N_2O, NH_3 and N_2 is performed using RF-PECVD reactor. The electrical characteristics of Al/HfO_2/GeON/p-Ge capacitors are investigated. Results show that the hysteresis of metal-oxide-semiconductor (MOS) capacitors with nitration-based passivation step is reduced to ～150 mV, compared with ～400mV of the untreated sample. The suppression of hysteresis is attributed to the reduction of electron traps and enhancement of dielectric/Ge interface quality. The improved interface quality of plasma-based nitration of Ge surface is a promising technique for high performance Ge MOSFET fabrication.