Influence of peripheral vibrations and traveling magnetic fields on VGF growth of Sb-doped Ge crystals

• Peripheral mechanical vibrations for doping homogenization were proposed.
• Novel bell-shaped vibrator was proposed.
• 3D simulations and experiments showed benefits of vibrational to TMF stirring.
• VGF growth of 4 in. Germanium was studied.

We performed 3D numerical and experimental studies to assess the potential of peripheral low frequency mechanical vibrations for improving the homogeneity of Sb-doped 4″ Ge crystals grown by vertical gradient freeze (VGF). For this study, a novel bell-shaped graphite vibrator was developed for the generation of the axial vibrations in the direction of three-phase junction. Melt stirring by downward traveling magnetic field (TMF) was used as a benchmark.The results showed superiority of peripheral vibrations to TMF stirring concerning radial and longitudinal doping distribution and initial stirring rate. Experimentally observed standing free surface waves in Ge were caused by shielding effect of the vibrator on TMF.