Study on defect annealing potential and bulk micro defect formation using high temperature RTA conditions for Cz‐grown silicon

Abstract

In this paper, the key parameters of a rapid thermal annealing (RTA) nitriding step are discussed with respect to vacancy- and oxygen precipitate (BMD)-profile formation. These RTA key performance parameters are the maximum NH3 dissociation temperature (i), the temperature stability of the stored vacancy peak (ii), and the defect dissolution capability of self Si agglomerates at elevated temperatures (iii). This parameter study could be helpful for a future model of the vacancy in-diffusion process into the Si near surface region. Especially the gate oxide integrity (GOI) is an important parameter to establish long life cycles in current memory devices. After NH3 RTA processing, it was surprisingly found that the GOI defect level is still influenced by small-sized grown in particles. It is demonstrated that a complete restoration toward a high GOI signal can be achieved via a 1300 °C RTA step. The gate oxide integrity is afterwards as good as observed on a defect free polished CZ wafer.