Segregation control in Czochralski crystal growth

Attempts have been made to control segregation during crystal growth. Two double crucible techniques and one single crucible technique have been developed to reduce segregation in the Czochralski-type growth of doped and alloyed semiconductor crystals.; A modified double crucible liquid encapsulation Czochralski technique (LEC) has been developed for the growth of InAs-doped GaAs crystals, using a long, large feeding tube at the bottom of the inner crucible. An InAs-doped GaAs crystal with a uniform InAs concentration of about 0.1 mole% was successfully grown via this technique.; A new double crucible liquid encapsulation Czochralski (LEC) process has been devised to grow macroscopically uniform InAs-doped and InAs-alloyed GaAs crystals. Unlike the conventional double crucible technique, the new process uses the gap between the inner and outer crucible as the passageway for the feeding source. It can separate the growth melt completely from the feeding melt. Both InAs-doped and InAs-alloyed GaAs crystals were successfully grown using this new process. The doped crystals had uniform InAs concentrations of 0.04 and 0.1 mole%. The alloyed crystals had uniform InAs concentrations of 1 and 2 mole%. All crystals were macroscopically uniform in composition in both the axial and radial directions.; A modified single crucible Czochralski method with bottom solid feeding has also been developed. This technique was used to control segregation during the liquid encapsulation Czochralski (LEC) growth of InAs-doped GaAs crystals. InAs-doped crystals with InAs concentrations of 0.04 and 0.1 mole% were successfully produced. This technique was also applied to grow SiGe alloy crystals with uniform concentrations with a solid feed of the targeted crystal composition. A single crystal with Ge content of 2.5 mole% was grown. All crystals grown by this process were macroscopically uniform in composition in both the axial and radial directions.