It was recalled that dislocation densities in compound semiconductor crystals had been found to be affected by the growth orientation, crystal radius and ambient temperature that was used during Czochralski growth. The present work investigated the effect of these parameters upon the dislocation density, and suggested methods for controlling the parameters so as to reduce the density. The finite element technique was used to solve the governing equations of quasi-steady state heat transfer and of thermo-elasticity in order to predict the temperature distributions and thermal stresses in a growing crystal. The resolved shear stresses on each slip system were deduced from the thermal stresses. The resolved shear stresses were then used to calculate the plastic deformation and dislocation density, on each slip system of the crystal, by using the constitutive equation. The total dislocation density in the crystal was obtained by summing the dislocation densities over all of the slip systems. The results indicated that a suitable choice of ambient temperature and growth direction could be used to reduce the dislocation density in Czochralski crystals.

The Numerical Modelling of Dislocation Generation in Semiconductor Crystals during Czochralski Growth. C.T.Tsai, N.Subramanyan: Modelling and Simulation in Materials Science and Engineering, 1995, 3[1], 93-105