X-ray characterization of bulk InP:S crystals crown by LEC in a low thermal gradient

Single crystals of S-doped InP grown with very low dislocation density under conditions of low axial and radial thermal gradients, are typified by a flat solid-liquid interface. For these crystals, the hot zone of the growth system is designed to sustain vertical, rather than radial heat flow through the crystal. The consequence of a reduced thermal gradient, together with the dislocation pinning effect of sulfur doping, produces single crystal InP crystals with EPD<500/cm² . Dislocations generated at the periphery of the growing crystal are blocked by the high S-concentration, especially at striations where high doping concentrations increase the critical resolved shear stress on a local scale