New Developments in Vertical Gradient Freeze Growth

The Vertical Gradient Freeze (VGF) technique is an important method for growing high quality compound semiconductors such as GaAs. Results obtained with a novel VGF set‐up developed for the growth under influence of a rotating magnetic field (RMF) and under vapour pressure control are presented in this paper. The RMF is shown to be a powerful tool to affect the heat and mass transport within the melt in a definite way. In GaAs:Si growth, RMF induced flow results in a decreased curvature of a nominally concave‐shaped interface, i.e., it contributes to an axial heat transfer at the solid‐liquid interface. The axial dopant segregation of Ga in Ge is found to be improved under continuous RMF action due to better mixing of the melt. The set‐up also allowed to determine the influence of carbon and the arsenic vapour pressure on the dopant incorporation and crystal quality.