Evaluation of the Mellen “EDG” furnace for growth of large diameter GaAs single crystals in a horizontal configuration

Abstract

An extensive evaluation of the Mellen “EDG” furnace has been conducted in order to assess its performance for growth of large diameter (2 and 3 inch) GaAs crystals in the horizontal configuration. The axial and radial temperature gradients were found to influence strongly the crystal-melt interface shape and crystalline perfection of the crystals. When the axial thermal gradients are small relative to the radial thermal gradients, the shape of the crystal-melt interface flactuates in time as growth proceeds, indicating the presence of oscillatory convective flows in the melt. The crystal-melt interface becomes stable as the axial component of the thermal gradient over the solid is increased. The crystals produced with optimized gradient conditions have a low and uniform dislocation density.