Hole energy dependent interface trap generation in MOSFET Si/SiO2 interface

Abstract

The nature and composition of generated interface-trap (ΔNIT) in p-MOSFETs is studied as a function of hole energy. By observing the time dependence of generation during stress and the amount of recovery after stress, it is shown that ΔNIT is due to both broken ≡Si--H and ≡Si--O-- bonds, their ratio governed by hole energy. In the absence of hot holes ΔNIT is primarily composed of broken ≡Si--H, which show a lower power-law time exponent and a fraction of which anneal after stress. Additional ΔNIT is created in the presence of hot holes, which is due to broken ≡Si--O-- bonds. These traps show a much larger power-law time exponent, and they do not anneal after stress. These observations have important implications for lifetime prediction under negative bias temperature instability, Fowler-Nordheim, and hot carrier injection stress conditions.