Single crystals of with dislocation and inclusion levels below 5/cm2 were grown in a nitrogen atmosphere with an infrared television system of computer controlled Czochralski crystal growth. Coring was prevented by a high crystal rotation rate and a slow pull rate during growth, although striations occurred in the crystal at high rotation rates. Dislocations were avoided by good crystal diameter control during growth and low thermal gradients in the crystal puller. Etching and polishing techniques were developed to reveal defects.