Effect of vibrational stirring on the quality of Bridgman-grown CdTe

The coupled vibrational stirring (CVS) method was applied to the vertical Bridgman growth of CdTe. This new stirring method involves orthogonally coupling a set of low frequency transverse vibrations to a growth ampoule. The motion imparted to the ampoule gives rise to rapid, controlled spiral flows. Dopant distributions in CVS grown, phosphorous-doped CdTe boules were studied by measuring free carrier concentrations. CVS improved the chemical homogeneity of Bridgman-grown crystals. From the isoconcentration curves, the growth interface was observed to be much flatter than in boules grown without CVS, which is desirable to minimize radial strain. Some degradation in microstructure was detected from the CVS processing conditions used in these experiments. This effect needs to be studied further.