硅中缺陷对Cu杂质的吸杂

Gettering of Copper by Defects in Silicon

本文采用快速热处理的方式引入Cu杂质,利用择优腐蚀以及光学显微镜研究了p型硅和n型硅中多种类型缺陷对Cu杂质沉淀行为的影响。研究发现,在p型硅中,当Cu杂质的浓度比较低时,硅体内的Cu杂质主要聚集和沉淀在位错或者晶界上,而当Cu杂质浓度较高时,Cu杂质可以在硅片内部无缺陷处形核沉淀,然而,晶界对Cu杂质的吸杂仍然表现比较明显,在晶界附近存在一个Cu沉淀很少的"洁净区"。在n型硅中,缺陷对Cu杂质的吸杂不明显。Cu杂质可以在缺陷处以及无缺陷处沉淀。但氧沉淀在n型硅中对Cu杂质的吸杂非常明显,并且氧沉淀还会阻碍Cu杂质在硅中的扩散。

Gettering of copper by defects in silicon was studied by preferential etching and optical microscopy. It was found that in p-type silicon, when the concentration of Cu impurity was not very high, most of the Cu precipitated on defects, including grain boundaries and dislocations; when heavily Cu contaminated, star-like Cu precipitates can be formed in silicon bulk, but defects also show great gettering effects for Cu, there was a precipitates ＂ DZ zone＂ along the grain boundaries. In n-type silicon, grain boundaries and dislocations showed little gettering effect for Cu, while oxygen precipitates exhibited great gettering effect for Cu impurity, as well as retard effect for the diffusion of Cu in silicon.