Negative Bias Temperature Instability of p-Channel Metal Oxide Semiconductor Field Effect Transistor with Novel HfxMoyNz Metal Gate Electrodes

Abstract

The negative bias temperature instability (NBTI) characteristics of p-channel metal oxide semiconductor field effect transistor (pMOSFET) devices with novel HfxMoyNz metal gates have been investigated for the first time. The threshold voltage (Vth) shift, subthreshold swing (SS), off-leakage current, and field effect mobility (µFE) were found to be degraded after NBTI stress. The possibility of nitrogen diffusing to the oxide is increased by employing a higher N2 ratio during HfxMoyNz deposition. The higher nitrogen content in HfxMoyNz metal gates shows threshold voltage (Vth) shift, subthreshold swing (SS), off-leakage current, and field effect mobility (µFE) degradation. The degradation of threshold voltage (Vth), subthreshold swing (SS), off-leakage current, and field effect mobility (µFE) are believed to be due to the interface states and fixed oxide charges generation from the broken Si–H bonds at the SiO2/Si interface. Furthermore, the mechanism of NBTI degradation has been suggested by a physical model and an energy band diagram.