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Studies of defect generation in CdZnTe and InP single crystals using synchrotron white beam x-ray topography.

机译：使用同步加速器白束X射线形貌研究CdZnTe和InP单晶中的缺陷生成。

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摘要

Synchrotron White Beam X-ray Topography (SWBXT), along with Lang topography, chemical etching analysis, TEM and Nomarski optical microscopy have been used for the characterization of defect structures in large CdZnTe and InP single crystals and for the determination of the nature of growth striations and the contrast formation mechanism in the images of growth striations in X-ray topography.; In the study of defect structures in CdZnTe single crystals, it was found that dislocations of very high density arrayed in a mosaic pattern were observed in all ground-base samples grown under identical growth conditions with flight samples except for the gravity conditions. Regions of very low dislocation density {dollar}({lcub}<{rcub}1000 rm cmsp{lcub}-2{rcub}){dollar} were observed in wafers sliced from steady-state growth regions solidified without wall contact.; Among the structural defects present in InP single crystals, the most pervasive ones are slip bands. X-ray topography revealed numerous slip bands nucleated from the peripheral regions and propagated into the interior of the crystal. The most likely origins for the formation of these structural defects are attributed to relieve large thermal stresses generated at the point where the hot solid material emerges from the encapsulant. A thermo-elastic finite element stress analysis for an intermediate growth stage also revealed that the maximum excess resolved shear stresses are generated on the outer surface of the crystal at the point where the crystal emerges from the encapsulant.; The growth interface morphology at different stages of a MLEK growth process is characterized through the observation of growth striations in longitudinal cut sulphur doped InP single crystals. Results revealed that the morphology of growth interfaces can be strongly influenced by the growth conditions.; The nature of growth striations as well as the contrast formation mechanisms in the images of growth striations on X-ray topography in sulphur doped InP sing!e crystals are investigated using a combination of various X-ray topographic techniques, TEM and chemical etching analysis. Results suggest that the formation of growth striations is attributed to the segregation of sulphur, which substitutes the atomic sites of phosphorus, leading to the generation of bulk stresses associated with lattice mismatches between layers of different dopant concentration.; Preliminary results in the investigation of twinning in (001) grown InP single crystals revealed a {dollar}{lcub}115{rcub}{dollar} scM-{dollar}{lcub}111{rcub}{dollar} scT orientation on the as-grown outer surfaces of the crystal across a twin boundary. Detailed studies including the local solid-liquid interface morphology and crystallographic orientation relationships revealed that the growth at a conical angle of {dollar}74.2spcirc{dollar} is the most dangerous one from the point of view of initiating twinning.; Back-reflection Laue diffraction patterns recorded from different twinned regions revealed the formation of {dollar}{lcub}110{rcub}{dollar} facets on the as-grown outer surfaces, while the matrix adjacent to the twin boundary is parallel to a {dollar}{lcub}114{rcub}{dollar} plane. (Abstract shortened by UMI.)
机译：同步加速器白束X射线形貌（SWBXT）以及Lang形貌，化学蚀刻分析，TEM和Nomarski光学显微镜已用于表征大型CdZnTe和InP单晶中的缺陷结构以及确定生长的性质X射线形貌生长条纹图像中的条纹和对比度形成机理。在研究CdZnTe单晶中的缺陷结构时，发现除了重力条件外，在与飞行样品相同的生长条件下生长的所有地基样品中均观察到以镶嵌图案排列的非常高密度的位错。在从没有壁接触而凝固的稳态生长区域切下的晶片中，观察到位错密度非常低的区域（美元）（{lcub} <{rcub} 1000 rm cmsp {lcub} -2 {rcub}）{美元}。在InP单晶中存在的结构缺陷中，最普遍的缺陷是滑带。 X射线形貌显示许多滑动带从外围区域成核，并传播到晶体内部。形成这些结构缺陷的最可能原因是减轻了在热固体材料从密封剂中出来时产生的巨大热应力。对中间生长阶段的热弹性有限元应力分析还表明，在晶体从密封剂中出来的那一点，在晶体的外表面上会产生最大的过量分解剪切应力。通过观察纵向切割的硫掺杂InP单晶中的生长条纹，可以表征MLEK生长过程不同阶段的生长界面形态。结果表明，生长界面的形态可以受到生长条件的强烈影响。使用多种X射线形貌技术，TEM和化学蚀刻分析相结合的方法，研究了硫掺杂InP单晶中X射线形貌上生长条纹的性质以及生长条纹图像中的对比度形成机理。结果表明，生长条纹的形成归因于硫的偏析，它替代了磷的原子位点，导致了与不同掺杂剂浓度的层之间晶格失配相关的整体应力的产生。在（001）生长的InP单晶中进行孪晶研究的初步结果显示，{as} {lcub} 115 {rcub} {dollar} scM- {dollar} {lcub} 111 {rcub} {dollar} scT取向-晶体的外表面越过孪生边界。包括局部固-液界面形态和晶体学取向关系在内的详细研究表明，从引发孪晶的角度来看，锥角为74.2spcirc {dol}的生长是最危险的。从不同孪晶区记录的背向反射劳厄衍射图谱显示，在生长的外表面上形成了{dollar} {lcub} 110 {rcub} {dollar}小平面，而与孪生边界相邻的矩阵平行于{美元} {lcub} 114 {rcub} {dollar}平面。 （摘要由UMI缩短。）

著录项

  • 作者

    Chung, Hua.;

  • 作者单位

    State University of New York at Stony Brook.;

  • 授予单位 State University of New York at Stony Brook.;
  • 学科 Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 1997
  • 页码 188 p.
  • 总页数 188
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;
  • 关键词

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