Effect of oxygen precipitates and induced dislocations on oxidation-induced stacking faults in nitrogen-doped Czochralski silicon

Abstract

The effect of oxygen precipitates and induced dislocations on oxidation-induced stacking faults (OSFs) in nitrogen-doped Czochralski (NCZ) silicon has been investigated. Both CZ and NCZ wafers were annealed at 800°C and 1000°C for 225h with or without a post-treatment at 1200°C for 8h, and then were totally oxidized at 1150°C. It was found that after oxidization, few OSFs generated in the NCZ silicon subjected to the annealing at 800 and 1000°C, while larger numbers of OSFs in the CZ silicon. However, if the post-treatment at 1200°C was employed prior to oxidization, OSFs density in the NCZ silicon was almost similar to that in the CZ silicon. It is considered that the high density of oxygen precipitates and induced dislocations formed in NCZ silicon can absorb the self-interstitial silicon atoms so that the generation of OSFs is inhibited. After the postannealing, most dislocations shrank and dissolved with the dissolution of oxygen precipitates in the NCZ silicon so as to induce the same amount of OSFs as that in the CZ silicon.