Evaluation of the Mellen ''EDG'' Furnace for Growth of Large Diameter GaAs Single Crystals in a Horizontal Configuration

摘要

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 in.) 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 fluctuates 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. 11 refs., 6 figs., 2 tabs. (ERA citation 13:001268)