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

Abstract

The nature and composition of generated interfacetrap (ΔN _IT) 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 ΔN _IT is due to both broken ≡Si–H and Si–O– bonds, their ratio governed by hole energy. In the absence of hot holes ΔN _IT is primarily composed of broken ≡Si–H, which show a lower power-law time exponent and a fraction of which anneal after stress. Additional ΔN _IT 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.