摘要
本文利用红外光谱和透射电镜研究了不同氧含量P-CZ硅中氧沉淀.根据微小粒子的光吸收理论所做的计算表明,片状沉淀和球形沉淀分别产生位于1220cm^(-1)和1090cm^(-1)的随波长缓慢变化的吸收,它们分别被指派为LO支和TO支吸收.已经将1220cm^(-1)和1090cm^(-1)吸收与实验上观察到的1224cm^(-1)和1075cm^(-1)吸收联系起来.低温退火过程中,大量沉淀的形成,特别是球形和针状沉淀的形成,导致了9μm带的宽化.我们还发现,经720℃106h+950℃二步退火的样品,9μm带随高温退火时间的延长,吸收率回复且向长波方向漂移.电镜观察表明,这时样品中含有大量八面体状沉淀.认为,这种八面体状沉淀产生了类似于球形沉淀的吸收,引起9μm带的反常变化.
The oxygen precipitation in P-CZ silicon with various oxygen content has been studied bymeans of IR absorption and TEM.The calculation based upon the theory of optical absorptionby small particles shows that platelet and spheric precipitates lead to the absorption bands locat-ed at about 1220 cm^(-1) and 1090 cm^(-1), respectively,which have been assigned to LO and TO bandsand related with experimentally observed 1224cm^(-1) and 1075 cm^(-1) absorption.It is believed thatthe formation of numerous precipitates, pecially the spherical and noddle-like,results inthe broadening of 9μm band during the low temperature annealing. It is found that in sam-pies undergoing two-step annealing, 720℃C106h + 950℃, the absorption of 9μm band recoveredand its peak shifted toward long wave direction.TEM observation shows the existence of a lotof octahedral precipitates in these samples, which is thought to produce the similar absorptionas that of spheric precipitates and to be responsible to the change of 9 μm band.
关键词
硅
氧沉淀
红外光谱
透射电镜
CZ Silicon
Oxygen precipitate
IR
TEM
9μm absorption
