Models for Stress and Dislocation Generation in Melt Based Compound Crystal Growth

A major issue in the growth of semiconductor crystals is the presence of line defects or dislocations. Dislocations are a major impediment to the usage of III–V and other compound semiconductor crystals in electronic, optical, and other applications. This chapter reviews the origins of dislocations in melt-based growth processes and models for stress-driven dislocation multiplication. These models are presented from the point of view of dislocations as the agents of plastic deformation required to relieve the thermal stresses generated in the crystal during melt-based growth processes. Consequently they take the form of viscoplastic constitutive equations for the deformation of the crystal taking into account the microdynamical details of dislocations such as dislocation velocities and interactions. The various aspects of these models are dealt in detail, and finally some representative numerical results are presented for the liquid encapsulated Czochralski (LEC) growth of InP crystals.