快速退火气氛对300mm硅片内洁净区和氧沉淀形成的影响

Effect of Rapid Thermal Annealing Ambient on Denuded Zone and Oxygen Precipitates in a 300mm Silicon Wafer

300mm硅片中厚度合适的洁净区和高密度氧沉淀,有利于对器件有源区金属沾污的吸除,改善栅氧化物的完整性.文中使用Ar,N2/NH3混合气作为快速退火(RTA)气氛,研究RTA气氛对洁净区、氧沉淀形成的影响.研究发现N2/NH3混合气氛处理的硅片表层洁净区明显薄于Ar气氛处理的硅片,氧沉淀密度明显高于Ar气氛处理后的硅片.同时发现在两种气氛下,延长恒温时间都可以降低洁净区厚度,增加氧沉淀密度.基于空位增强氧沉淀成核和氮化空位注入的基本原理,就RTA气氛和恒温时间对洁净区和氧沉淀分布的影响进行了讨论.

In a 300ram silicon wafer,a suitable denuded zone depth and a high oxygen precipitate density are necessary to get a high gettering efficiency and to improve the gate oxide integrity （GOI）. In this work,Ar and an N2/NH3 mixture gas are applied as rapid thermal annealing （RTA） ambients. It is demonstrated that a high density of oxygen precipitate and a thin denuded zone are obtained in the N2/NH3 mixture ambient, while a low density of oxygen precipitate and a thick denuded zone are observed in the wafer annealed in the Ar ambient. The effect of the RTA ambient and annealing time on the denuded zone and oxygen precipitates is discussed.