Low-dislocation-density 4" 0 /spl Oslash/ GaAs single crystal growth under arsenic atmosphere

By using our VCZ (Vapour pressure controlled Czochralski) method, we successfully grew semi-insulating 4 /spl oslash/ GaAs single crystals with very low-dislocation density of less than 5,000cm/sup -2/ which was one order of magnitude less than that of the LEC single crystal. The residual strain of the VCZ substrate was one quarter of that of the LEC substrate. The generation of slip-dislocation on the substrates during MBE (Molecular Beam Epitaxy) growth was significantly improved on the VCZ substrates.