Development of a Comprehensive Model for Horizontal Bridgman Growth of IR Materials

Development of a comprehensive model for Horizontal Bridgman (HB) growth of infrared materials is proposed. The horizontal Bridgman technique is a primary process for growth of IR as well as opto-electronic quality GaAs crystals. Yet, our ability to quantitatively predict the influence of various growth and growth system parameters on the device-critical properties of the materials grown by this technique remains extremely limited. A team of three companies isformed to develop an HB computational simulator based on latest advances in process modelling and numerial techniques, and growth experiments focused on model validation. The proposed model will be able to simulate the entire solidification process from onset of growth to cooldown to room temperature, and will rigorously capture radiative exchanges in the three-dimensional growth geometry including internal radiation in the semi-transparent crystal. The model will calculate the unsteady temperature, velocity, and concentration fields in the charge, elastic and inelastic stresses in the crystal, and will track the shape and position of the crystal-melt interface. The simulator is designed to be useable by practicing engineers, and thus, will be equipped with powerful graphic user interfaces to insulate the user from gridding and computational details. Anticipated Benefits: The availability of a robust and validated simulator for the Horizontal Bridgman technique will introduce, for the first time, leading-edge process design and analysis capability toan important commercial sector of the materials industry involved with proudction of infrared and III-V opto-electronic materials. This capability is expected to expand the science base of HB growth process, and identify hardware and process modifications needed to improve the qulity of grown materials and the process yield.