POINT DEFECT GENERATION DURING Si OXIDATION AND OXYNITRIDATION

摘要

In conclusion we have studied the influence of interfacial nitrogen on point defect injection kinetics during a) N_2O oxidation and b) dry oxidation of N-implanted silicon. It was shown that oxidation in N_2O ambient at high temperatures leads to enhanced supersaturation of silicon interstitials. This behavior is attributed to the existence of a nitrogen-rich layer near the Si-SiO_2 interface; this obstructs the diffusion of silicon interstitials into the oxide and reduces reaction sites where they can be incorporated in the oxide, thus greatly enhancing the fraction of interstitials that are injected into the silicon. However, for lower temperatures this phenomenon is reversed, as less nitrogen is incorporated at the interface and oxidation in N_2O ambient leads to reduced interstitial supersaturation compared to dry one. In contrast, dry oxidation of N_2 implanted silicon substrates does not lead to significant enhancement of interstitial supersaturation, at least for all times. This was attributed to the different kinetics of nitrogen in this case.