热处理CZ-Si中新施主与氧沉淀产物的对应关系

RELATIONSHIP BETWEEN NEW DONOR AND OXIDE PRECl-PITATES IN ANNEALED CZ-SILICON

本文利用霍耳测量、红外测量及透射电子显微镜等手段,对热处理CZ-Si中的新施主及氧沉淀进行了研究。常规电子显微镜(TEM)结果表明,经650—750℃热处理的CZ-Si中主要形成点状及杆状缺陷。新施主的形成与点状缺陷关系密切。根据高分辨电子显微镜(HREM)观察,这些点状缺陷相当于晶体结构为β-方石英的片状SiO_2晶态沉淀,它们与硅基体界面上有半数硅原子处于失配状态,失配原子的悬挂键可以成为新施主的来源。新施主的产生受控于β-方石英沉淀物的形核、长大及其结构变化。

New donor and oxygen precipitate in CZ-silicon are studied by means of Hall measurement, IR measurement and TEM observation. Two types of defect are observed in specimens annealed at 650-750℃, that is, rod-like defects and plate-like defects. New donor generation is mainly related to the plate-like defects, which are indentified as β_cristobalite according to the H-REM results. It is suggested that the new donor originates from the ionization of dangling bonds of silicon atoms on precipitates/matrix interfaces and is controlled by the neucleation and growth of β_cristobalite precipitates.