Zone Refining High-Purity Germanium

The effects of various parameters on germanium purification by zone refining have been examined. These parameters include the germanium container and container coatings, ambient gas and other operating conditions. Four methods of refining are presented which reproducibly yield 3.5 kg germanium ingots from which high purity (¿NA - ND¿ ¿2 × 1010 cm-3) single crystals can be grown. A qualitative model involving binary and ternary complexes of Si, 0, B, and Al is shown to account for the behavior of impurities at these low concentrations.