Generation of hole traps in thin silicon oxide layers under high-field electron injection

Abstract

The letter reports an observation of a new degradation mechanism in thermal silicon dioxide layers on silicon, namely generation of hole traps under high-field stressing of metal-oxide-semiconductor (MOS) structure. Excess hole trapping due to newly generated hole traps is observed by substrate hot-hole injection in 9 nm oxide of p-channel MOS transistors after high-field Fowler-Nordheim stress followed by standard post-metallization annealing in nitrogen. The concentration of generated traps has a weak stress-polarity dependence and increases with electron fluence during degrading stress. Relaxation behavior under switching oxide fields indicates that the nature of hole trapping sites is different from anomalous positive charge centers.