Water trapping of point defects in interlayer SiO2 films and its contribution to the reduction of hot-carrier degradation

Abstract

The water-blocking effect of plasma chemical vapor deposition (CVD) SiO2 film is investigated. Using electron spin resonance measurements, point defects in the electron cyclotron resonance (ECR) plasma CVD SiO2 used in this work can be identified as dangling bonds belonging to Si atoms. The defect density is reduced by capping water-containing film on it, suggesting that the defect is capable of trapping water. The hot-carrier degradation in a metal-oxide-semiconductor (MOS) device is successfully prevented when ECR plasma CVD SiO2 is used as a water-blocking layer that keeps water in the overlayer from diffusing to the gate oxide. This result indicates that ECR plasma CVD SiO2 effectively blocks water due to the water trapping ability of the Si dangling bonds.