Low-dislocation-density and low-residual-strain semi-insulating GaAs grown by vertical boat method

Semi-insulating 4" /spl phi/ GaAs single crystals of 20 cm in length have been grown by the Vertical Boat(VB) method. The crystals have extremely low dislocation density between 1000 and 2000 cm/sup -2/, and have extremely low residual strain between 2/spl times/10/sup -6/ and 3/spl times/10/sup -6/. Good controllability of the carbon concentration and the resistivity have been achieved by doping carbon from a carbon source. The crystals have uniform distribution of carbon along the growth axis. The concave shape of the solid-liquid interface was improved by applying computer simulation and lineage formation was suppressed.