Susumu Sugano

6-in diameter InP single crystals grown by the hot-wall LEC method and the mirror wafers

6-in diameter Fe-doped semi-insulating InP single crystals have been grown by the hot-wall liquid encapsulated Czochralski method. This method has a quartz inner vessel to stabilize the thermal convection. Temperature gradient and solid-liquid interface shape can be controlled by a multizone heater system. The weight of grown crystal was 18 kg and the full length was 250 mm. The dislocation density was about 1/spl times/10/sup 5/ cm/sup -2/. The resistivity was more than 1/spl times/10/sup 7/ /spl Omega/cm and its uniformity was the same as the smaller diameter crystal. The conditions of wafer processing were optimized to improve the wafer flatness. The rolloff and the slope of the wafer surface could be reduced especially by the improvement of the polishing conditions. The typical total thickness variation was 3.3 /spl mu/m, and it was comparable to the GaAs wafer.