Dislocation density control in high-purity germanium crystal growth

High-purity germanium (HP-Ge) crystals were grown in hydrogen atmosphere by Czochralski method. The control of dislocation density in high-purity germanium crystal growth was studied. It could be shown that by control of the temperature gradient during crystal growth the dislocation density distribution in the crystal can be controlled to a degree which allows for the growth of crystal fulfilling detector requirements. Crystals with diameters of 3.5 and 9 cm were grown according to the relationship between axial temperature gradient and dislocation density to be able to meet the requirements of detector fabrication by having dislocation density in the range 2000-7000 cm−2.