锗/硅短周期超晶格的X射线双晶衍射研究  

A double-crystal XRD study of Ge/Si short period superlattice

作　　者：季振国[1] 袁骏[1] 卢焕明[1] 芮祥新[1] 王龙成[1] 

机构地区：[1]浙江大学硅材料国家重点实验室,浙江杭州310027

出　　处：《浙江大学学报（工学版）》2001年第1期1-4,共4页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目 !(6 9776 0 0 6 )

摘　　要：用 X射线双晶衍射对气源分子束外延 (GS- MBE)制备的锗 /硅短周期超晶格 (SPS)样品进行了分析。所有样品的锗层厚度固定为 1.5单原子层 ,而硅层厚度为 1.4～ 3.8nm。对于硅层厚度小于 2 .4nm的样品来说 ,双晶衍射摇摆曲线中由超晶格引起的衍射峰较宽 ,而且看不到干涉引起的精细结构 ,这表明超晶格中可能存在位错及界面不平整。对硅层较厚 (>2 .9nm)的样品 ,摇摆曲线中超晶格引起的衍射峰很窄 ,而且有明显的由干涉产生的精细结构 ,表明此时超晶格的质量较高 ,界面平整。对硅层厚度为2 .1～ 2 .9nm的样品 ,超晶格对应的衍射峰可以分解为两个宽度不等的子峰 ,但没有精细结构出现。这个区间与文献 [1]报道的在荧光光谱发现的一个异常带出现区间完全相同。本实验的 X射线双晶衍射测试与分析结果支持文献Ge/Si short period superlattice (SPS) samples consisting of 1.5 mono\|layer Ge and 1.4-3.8 nm thick Si layer grown by gas source molecular beam epitaxy (GS\|MBE) were studied by double crystal X\|ray diffraction. For SPS samples with Si layer less than 2.4 nm, the satellite peaks caused by SPS structure in the rocking curve are quite broad and without fine interference structure. For SPS samples with thick Si layer, the rocking curves are sharp and fine interference structures exist. For SPS samples with Si layer thickness (\%L\%\-\{Si\}) between 2.1 nm and 2.9 nm, both broad and sharp peaks exist but without fine structure. Our results strongly support H. Sunamura's suggestion that the abnormal photoluminescence band in such SPS structure is caused by waviness formation of epi\|layer due to vertical correlation of thickness fluctuations by local strain field.

关 键 词：锗 硅 短周期 超晶格 双晶衍射 

分 类 号：O434.14[机械工程—光学工程] O471[理学—光学]