氮对直拉硅片中氧沉淀分布的影响

Effect of Nitrogen on Oxygen Precipitate Profile in Czochralski Silicon Wafer

研究了氮在退火过程中对直拉硅片中的氧沉淀分布的影响 .实验结果表明 ,三步退火后在掺氮硅片截面形成特殊的 M形的氧沉淀密度分布 ,即表面形成没有氧沉淀的洁净区 (DZ) ,体内靠近 DZ区域形成高密度、小尺寸的氧沉淀 ,而在硅片的中心处形成低密度、大尺寸的氧沉淀 .分析认为 ,由于在第一步高温退火过程中氮在硅片表面外扩散 ,同时在硅片体内促进氧沉淀 ,改变了间隙氧的分布 。

The effect of nitrogen on oxygen precipitate profile in Czochralski (CZ) silicon wafer is investigated. A M like depth profile of oxygen precipitate density is observed in the nitrogen doped Czochralski silicon (NCZ Si) wafer subjected to three step annealing (1150℃,4h+650℃,128h+1050℃,16h). Perfect DZ forms in the near surface region.Small oxygen precipitates with high density appear in the adjacent region of the denuded zone (DZ) inside of the bulk.And large oxygen precipitates with low density appear in the center bulk region. It is considered that the M like depth profile of oxygen precipitate density in the NCZ Si wafer is closely related to the depth profiles of interstitial oxygen concentration during the three step annealing process and nitrogen out diffusion at high temperature, as well as the effect of nitrogen enhancement on the oxygen precipitation.