Influence of Low Axial Temperature Gradient on Ga-Doped Germanium Crystal Growth by the Vertical Bridgman Method

The influence of a low axial temperature gradient on the growth of the Ge:Ga crystal by the vertical Bridgman technique was investigated. The axial temperature gradient of 3.3 K/cm is shown to provide conditions for polycrystalline growth of Ge:Ga crystals. The layers with the distances from 14 to 277 μm are found in the grown crystals with a concave of the solid-liquid interface. The motion of textolite particles in distilled water is visualized by the light cut method at different values of axial and radial temperature gradients. In the absence of the radial temperature gradient, no convection is observed when the axial temperature gradient increases from 0.1 to 6.5 K/cm. In this case, the particle motion velocity increases proportionally to the axial temperature gradient due to the occurrence of thermal diffusion. The convective flow appear in the liquid at the radial temperature gradient of 0.6 K/cm and an axial gradient above 0.1 K/cm.