MEETING DEVICE NEEDS THROUGH MELT GROWTH OF LARGE-DIAMETER ELEMENTAL AND COMPOUND SEMICONDUCTORS

High-quality, large-diameter semiconductor wafers are required by the device engineer because of the well-known yield advantages of large-ar ea wafer processing. Yet the growth of large semiconductor single crys tals with high compositional purity, low concentrations of stoichiomet ric and point defects, and high crystalline perfection becomes increas ingly difficult as one progresses from elemental Si and Ge, through th e III-Vs to the II-VI compounds. For example, dislocation-free Si crys tals can be grown up to at least eight-inch diameter, GaAs crystals up to four-inch diameter but containing high dislocation densities, whil e CdTe can only be prepared as large-grain polycrystalline two-inch di ameter ingots. Limitations are imposed by the fundamental thermophysic al constants of latent heat, thermal conductivity, and critical resolv ed shear stress, which present significant challenges to the crystal g rower. This presentation reviews progress made in the melt growth of t hese semiconductors as large-diameter crystals. How well the current n eeds of the device community are being met, and new potential device o pportunities made possible as a result of the progress in crystal grow th, will be illustrated.