含氢气氛下区熔硅单晶中缺陷的研究

利用化学腐蚀和X射线投影貌相方法研究了含氢气氛下区熔无位错硅单晶中的缺陷,发现异常腐蚀现象、缺陷密度与气氛中氢含量紧密相关,观测了纯氢气氛下无位错硅单晶退火后的缺陷,找到了貌相与蚀象的对应关系,还观察了二次退火效应,最后,综合所观测到的结果,讨论了氢在硅单晶中的集聚、沉淀和位错环列的发射、运动及交互作用。 关键词：

INVESTIGATION OF THE DEFECTS IN SILICON SINGLE CRYSTALS GROWN BY FLOATING-ZONE METHOD IN THE ATMOSPHERE CONTAINING HYDROGEN

Defects in dislocation-free silicon single crystals grown by floating-zone method in the atmosphere containing Ar-H₂ or H₂ were investigated by means of chemical etching and X-ray projection topography. It has been found that anomalous etch pits and defect density are closely related to the hydrogen content. (Change of the defect density with hydrogen content shows a maximum at approximately 10% hydrogen for ay-grown crystals. After annealing at high temperatures, the defect density in the inner part of the crystal is found to be more than that at the surface and also more than that in as-grown state when hydrogen content is greater than 25% in the atmosphere.) Defects in annealed crystals grown in the pure hydrogen atmosphere have been observed. The relationship between some defects showing in topographs and etch patterns was found. Effect of annealing on wafer with these defects was also observed. Finally, clustering and precipitating of hydrogen have been discussed. Dislocation loops formed at precipitate-matrix interface were described. The process of motion and interaction of the loops as well as the forming of multi-centre loops at high temperatures were also discussed briefly.