Growth of Germanium for Lithium Drift Detectors

The germanium for lithium drift germanium detectors should have the following properties: 1. High lithium drift rate. 2. Low reverse current during the drifting process - particularly for high temperature drifting. 3. Minimal lithium precipation during drifting. 4. Capability of fabrication into detectors exhibiting (a) Low noise reverse currents at high bias voltages (b) A minimum of carrier trapping. Germanium grown in a hydrogen atmosphere exhibits most of these desirable qualities. Measurements of ρ, τ, dislocation density, Hall mobility, conductivity, and IR absorption on both hydrogen grown and normally grown crystals have been made for correlation with detector properties. These measurements and the details of the hydrogen growth process are discussed.