Numerical analysis on Hg1-xCdxTe growth by ACRT-VBM

The ACRT-VBM growth process of Hg1-xCdxTe crystal has been numerically anal yzed by the finite difference method. The forced convection resulting from the accelerated crucible rotation technique (ACRT) and its effects on the p osition and the shape of the melt/crystal interface are studied, and the so lute redistribution and radial segregation are evaluated. The results show that during ACRT process the convection vortex in the melt appears, develop s, declines and disappears periodically according to the periodic change of the crucible rotations. Corresponding to the periodic change of the flow f ield, the growth rate, the temperature and concentration oscillate periodic ally. When ACRT with certain crucible rotation sequence is applied to the B ridgman crystal growth process of Hg1-xCdxTe, the interface depth decreases markedly as the results of the solute transport effect of ACRT flow. The p roper crucible rotation sequence is "the discontinuous triangle wave" consi sting of the acceleration, deceleration and rest periods. For the Hg1-xCdxT e crystal with a radius of 0.60 cm, the period (T-ACRT) of 36 s and the max imum rotation rate (w(max)) about 45 rpm are preferable. (C) 2000 Elsevier Science B.V. All rights reserved.