The single crystal growth and characterization of indium phosphide

Abstract

The authors have grown dislocation-free and defect-free InP single crystals, doped with sulphur or zinc, by means of the liquid encapsulation Czochralski technique. The perfection of the crystals was studied by transmission X-ray topography and preferential etching. By optimizing the growth conditions, in particular the temperature gradient in the crystal, the generation of dislocations could be suppressed at doping levels as low as 2×10 18 cm -3 in sulphur-doped crystals and 1×10 18 cm -3 in zinc-doped crystals. Via chemical analysis of the first-to-freeze portions of the crystals the effective distribution coefficients of sulphur and zinc were calculated and compared with earlier published data. In one sulphur-doped crystal unusual inclusions (“grappes”) were detected at a density of 2×10 4 cm -3. They were analyzed by preferential etching, scanning electron microscopy and energy dispersive X-ray analysis and were found to consist of a central core surrounded by dislocation loop arrays in the four 〈110〉 directions. The mechanism underlying the formation of these inclusions is discussed.