Crystal pulling with a floating nonwetted shaper

In crystal growth by pulling from the melt, the crystal cross-section can be controlled with the help of a shaper, which in the case of semiconductor and metal single crystals is usually lighter than and not wetted by the melt. In order to better control the crystal cross-section, we controlled the temperature near the aperture of the shaper during crystal growth. Graphite was used as a floating shaper and in order to allow close observation of crystal growth, a low melting-point material, i.e., Sn, was chosen as the melt. Single crystals were grown with excellent control over the cross-sectional shape and size. Single crystals were also grown under two other conditions, i.e., no temperature control and crucible temperature control. The control over the crystal cross-section in these two cases, however, was inferior to that in the case of shaper (aperture) temperature control. This difference was explained with the help of knowledge of the shaper (aperture) temperature, which was measured in each of the three cases.