Study of the SiO2/Si interface endurance property during rapid thermal nitridation and reoxidation processing

Abstract

The effects of rapid thermal nitridation of oxides (RTN) and rapid thermal reoxidation of rapid thermal nitride oxides (RTO/RTN) on the SiO2/Si interface endurance property have been studied. It is found that in order to enhance the SixNyOz/Si interface ‘‘hardness’’ [i.e., less interface states (Dit) are generated during high electric field stress], an interfacial oxidation process during RTN or RTO/RTN must occur. This oxidation reaction not only removes the nitridation-induced damages but also grows an interfacial strainless oxide. The existence of small amounts of nitrogen at the interface is responsible for the strainless oxide growth, and hence the improvement of SixNyOz/Si interface strength. A physical model based on these observations is described, which considers the generation of silicon and oxygen dangling bonds at the SixNyOz/Si interface during rapid thermal processing.