A new double crucible technique for LEC growth of In-doped GaAs crystals

摘要

A new double crucible technique was used in the liquid-encapsulated Czochralski (LEC) growth of In-doped GaAs to grow single crystals homogeneous in composition (0.04 and 0.1 mol% InAs). The inner crucible holding the melt for crystal growth was slightly smaller in diameter than the outer crucible holding the melt for replenishing. Unlike in previous studies, the replenishing melt did not have to go through a hole or tube at the bottom of the inner crucible, which can be plugged by the liquid encapsulant B_2O_3 during crystal growth. Rather, the replenishing melt was forced to go up through the narrow gap between the crucibles and enter the inner crucible from the top. Initially, a ring-shaped baffle was provided at the top of the inner crucible to make the replenishing melt mix well with the growth melt as it entered the inner crucible. Later, however, such a baffle was found unnecessary. Single crystals were grown with uniform InAs concentrations both in the axial and radial directions, without as well as with a baffle.