Numerical simulation of semiconductor crystal growth by directional melt solidification

A new method is suggested for solving the Stefan problem for crystal growth by directional solidification. The problem is treated as an essentially un steady one. The conditions ensuring a constant growth rate and the controll ability of the shape of the crystallization front are found. The observed a nd calculated data are in satisfactory agreement. The effect of an oscillat ing external force on the melt that initiates macrosegregation is analyzed. It is demonstrated that fluctuations of the crystal growth rate cause the formation of transverse growth striations. The radial inhomogeneity of the crystal is investigated.