Computed stress fields in GaAs during vertical Bridgman growth

VGF growth of germanium single crystals without crucible contact

“…Due to different heat conductivities and thermal expansions at the crystal-crucible interface these stresses are of thermal and thermo-mechanical origin. In [26] numerical investigations of the stress field in a cylindrical crystal under an unspecified stress given via the boundary conditions were presented. It was figured out that the stress level increases not only in the vicinity of the periphery but also in the whole solid domain.…”

Effect of constrained growth on defect structures in microgravity grown CdZnTe boules

“…Calculations from stress field models for vertical Bridgman growth 24,25 clearly show that stress levels in the peripheral wall contact regions are nearly an order of magnitude higher than those in crystals growing without wall contact. This provides a suitable environment for studying effects on crystal growth due to gravity-independent factors.…”

“…Stress models 24,25 clearly show that the shouldering operation generated very high stresses and static friction in this region could significantly increase the local stresses. Numerous grains appear to have been nucleated and twins could also be discerned.…”

Numerical Study of Thermal Stresses for the Semiconductor CdZnTe in Vertical Bridgman

“…And a smaller thermal stresses can be achieved by reducing both the radial and the axial temperature gradients. Rosch et al [14] investigated the interaction of the ampoule and GaAs crystal in a vertical Bridgman furnace. Their study proved that sticking is the primary cause of excess stress, but it can be reduced by matching the thermal expansion coefficient of the ampoule to the crystal.…”