The Effects of Heat Treatments of Germanium on Resistivity, Photoconductive Decay and on Lithium Drift Properties

The effects of heat treatments on resistivity, photoconductive decay and Lithium drift properties of p-type germanium single crystals have been investigated. We found that, in contrast to literature thermally produced acceptors cannot be reconverted if vacuum is used instead of a gas during "anneal" treatments. Vacuum heat treatments also lead to a stronger decrease of the photoconductive decay time than a gas atmosphere does. Close to theoretical Lithium drift rates considerably decrease in heat treatments, poor drift rates can be improved. The effects of quenching differs distinctly from those of slow cooling. The surface exposed to vacuum can be assumed to be a more abundant source of single vacancies due to a lower density of sorption engagements. Single vacancies diffuse then rapidly into the bulk and become less mobile in interactions, possibly with (interstitial) copper, thus providing stable p-sites.