Segregation control in vertical Bridgman single crystal growth by ACRT and AVT
Date Issued
2007
Date
2007
Author(s)
Wang, Liang-Cheng
DOI
zh-TW
Abstract
The aim of the investigations presented here is to analyze experimentally the effect of convection cause by angular vibration technique (AVT) and accelerated crucible rotate technique (ACRT) during the vertical Bridgman method. The convection pattern in the melt and the shape of the solid-liquid interface are two crucial internal parameters that may cause the inhomogeneities in the grown crystal. An external force added in the experiment is the best method to restrain the inhomogeneities in the grown crystal. In the past, there are some group apply electromagnetic field to control the flow pattern. But this method is restricted at electric materials only. So our motivation is that, we expect to reduce the inhomogeneities in axial and radial direction by applying angular vibration technique (AVT) and accelerated crucible rotate technique (ACRT) method. Further, we can obtain a more uniform doping crystal.
In this thesis, we apply this technique to germanium alloys. After take out the grown crystal, we cut the slice along the axial direction. And then we will etch the slice to see the interfaces or striations after lapped and polished. And then, we use Four-Point Probe or Electron Probe X-Ray Micro-Analyzer (EPMA) to measure the concentration profile in axial and radial direction. Finally, we will discuss effects of interface shapes, striations, and concentration distribution after adding angular vibration technique (AVT) and accelerated crucible rotate technique (ACRT) method.
Subjects
垂直布氏法
偏析
vertical Bridgman method
segregation
Type
thesis
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