直拉型Si单晶中金属杂质对氧沉淀行为的影响

Influence of Metallic Impurities on Oxygen Precipitation in Czochralski-Grown Silicon

本文研究了直拉型Si单晶中Cu和Fe杂质对氧沉淀行为的影响．尽管Si晶体中Cu杂质的浓度远高于Fe杂质，但发现Cu对氧沉淀行为没有影响，而Fe会明显增强氧的沉淀速率．实验结果表明Cu在Si中形成低密度、大尺寸的沉淀物团簇，与Si晶体生长后业已存在的微小氧沉淀物中的绝大多数没有相互作用；相反地，Fe杂质与微小氧沉淀物相互作用，形成高温下稳定的复合粒子，充当了氧沉淀的有效成核中心．

Oxygen precipitation in Czochralski-grown silicon (CZ-Si)intentionally contaminated with Cu of Fe is investigated by means of FOurier-transform infrared spectroscopy (FTIR), the electron-beam-induced-current (EBIC) technique and transmission electron microscopy (TEM). It is found that oxygen precipitation is not influenced by Cu impurities, but enhanced significantly by Fe impurities even if the concentration of Fe is much lower than that of Cu in Si. Cu forms precipitate colonies of a low density and a big size, and does not react with minute oxygen precipitates existing in as-grown specimens. Contrarily, Fe precipitates on them and forms Fe decorated silica particles of a very high density, which serve as the efficient sites for the nucleation of oxygen precipitates.