Mobility of Radiation-Induced Defects in Germanium

Abstract

The motion of irradiation‐produced defects in germanium has been observed under the influence of the electric field of a reverse‐biased p‐n junction. The defects were created with 1‐Mev electrons or Co⁶⁰ gamma rays, and the spatial distribution of the defects was obtained from the bias dependence of the junction capacity. Motion in the electric field was observable between 40–70°C and corresponds to negatively charged centers with a mobility of 2.6×10⁻¹⁴ cm²/v sec at 65°C. The activation energy of the mobility is about 1 ev. The centers are thought to be those which have previously been observed to anneal thermally. No observable effect was found for those defects which anneal at lower temperatures. Tentative interpretations are given.