Preparation of high purity germanium single crystal and analysis of dislocation density

Abstract: High purity germanium detector plays an important role in the field of radiation detection. High purity germanium with 13N purity and dislocation density between 100 ~ 10 000 cm-2 was successfully prepared through zone melting purification and single crystal growth. In the zone melting experiment, the self-made horizontal zone furnace is used to achieve the purification requirements through 20 ~ 50 times of zone melting in the environment of high-purity hydrogen. The single crystal is grown by Czochralski method along the [100] direction in high-purity hydrogen environment with effective length > 50 mm and effective diameter > 30 mm. The dislocation density measurement adopts the etching method. The acid etching solution is used to etch the crystal (100) surface and the number of the etch pits is counted. The results show that the dislocation densities at 25, 50 and 72 mm from the head of the single crystal are 2 537, 3 425 and 4 075 cm-2 respectively. These results indicate that the dislocation density before 72 mm meets the requirements for the preparation of high-purity germanium detectors. The research can provide reference for the preparation of high purity germanium single crystal.