Foreign atom thermodynamics in liquid gallium arsenide

Abstract

Thermodynamic equilibrium in gallium arsenide crystal growth systems with the components Ga–As–C–B–N–Si–O has been analysed by using a Gibbs energy minimisation computer package. Emphasis is placed on graphical representations to describe the behaviour of C, B, Si and O in the crystal growth melt at 1513 K. The various experimentally observed correlations between solute elements in the liquid and the encapsulant are rationalised. Additionally, guidance is provided for improvements in the design of crystal growth operations. Instead of relying on the current procedure of maintaining purity control on the input materials and standardised operating conditions, it is suggested that the flow of wet CO or H 2/CO 2 input gas flow mixtures be used to fix C and O activities and, thereby, reduce the thermodynamic degrees of freedom of the system to zero.