Adaptive Phase Field Modeling of Morphological Instability in Directional Solidification of SiGe Alloy
Date Issued
2012
Date
2012
Author(s)
Chen, Hung-Yu
Abstract
In the solidification process, the morphological instability of solidification is a very important problem, people had discussed some metal or organic material such as NiCu and SCN-ACT for this topic very well. But because of the high melting point of silicon, there are few paper discuss the instability phenomenon for silicon growth. From 2002, Fujiwara et al. had published some experiment result for silicon growth, and from 2009, they published more experiment for the instability phenomenon for silicon and silicon –germanium. At first we use the parameter given by Fujiwara, they claim the temperature gradient of the system is 8 K/mm, but we can’t simulate the instability. And then we use the classical theory and heat transfer analysis, we found that the temperature gradient is 1 K/mm, and by using the parameter we can found the instability phenomenon in 2D simulation. We also discuss the impact of some physical parameters, such as the cusp kinetic is the requirement and the role of the surface energy anisotropy is determining the wavelength of instable pattern. In the SiGe system, we found the SiGe instability follow the classical theory and the instability behavior is independent of orientation, both of the two conclusion is the same as Fujiwara et al claim. Finally, we simulate the morphology like experiment result very well for 15 at% Ge.
Subjects
facet growth
morphological instability
s-silicon
silicon-germanium
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-101-R99524073-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):348a8a52aa6a751208189c77c7771299