On the generation and recovery of interface traps in MOSFETs subjected to NBTI, FN and HCI stress

Abstract

A common framework for interface-trap (N_IT) generation involving broken ≡Si-H and ≡Si-O bonds is developed for Negative Bias Temperature Instability (NBTI), Fowler-Nordheim (FN) and Hot-carrier Injection (HCI) stress. Holes (from inversion layer for pMOSFET NBTI, from channel due to impact ionization and from gate poly due to anode-hole injection or valence-band hole tunneling for nMOSFET HCI) break ≡Si-H bonds, whose time evolution is governed by either one-dimensional (NBTI or FN) or two-dimensional (HCI) reaction-diffusion models. Hot holes break ≡Si-O bonds during both FN and HCI stress. Power-law time exponent of N_IT) during stress and recovery of N_IT) after stress are governed by relative contribution of broken ≡Si-H and ≡Si-O bonds (determined by cold- and hot-hole densities) and have important implications for lifetime prediction under NBTI, FN and HCI stress conditions