ON VOIDS IN INXGA1-XSB CRYSTALS GROWN BY AN ULTRASONIC-INTRODUCED VIBRATION-INTRODUCED CZOCHRALSKI METHOD

The shape and size of voids, and the grown region surrounding a large void were investigated in InxGa1-xSb crystals, which were pulled under the introduction of ultrasonic vibrations into the source melt by usi ng a modified Czochralski apparatus. The presence of voids in crystals resulted from (1) atmosphere gas was confined beneath the growth inte rface of a seed crystal during the seeding procedure, and (2) many bub bles - generated by the cavitation effect due to ultrasonic vibrations - were caught in the growing crystal. Voids were circular, deformed t rapezoid, and complex in shape, and were in a range of 20 mum to 3 mm in size. Even in case of a void with the diameter as large as 2 mm, th e grown region surrounding it was in the single crystalline state. In this interesting region, the microscopic variation of In concentration and the abrupt change of growth rate were observed.