Annealing of electron-induced defects in n-type germanium

Abstract

n-type, 1013 and 2 × 1015 cm-3 doped germanium has been irradiated with 1-MeV electrons at liquid-helium and room temperatures. With the use of transient-capacitance spectroscopy, six electron traps and one hole trap were observed following irradiation at 4 K. Their energy levels have been determined to be at Ec-40, 120, 120, 260, 390, and 530 meV, and at Ev+250 meV. The isochronal annealing behavior of these traps, in addition to that of the four electron traps and of the four hole traps produced by room-temperature irradiation, has been studied in detail. Comparison of our results with previously published ones indicates that (i) the divacancy anneals around 150°C and the E center around 100°C, (ii) the two levels at Ec-120 meV are associated with the germanium interstitial or complexes involving a germanium interstitial, and (iii) there appears to be a vacancy level in the range 100-200 meV from the conduction band, which anneals at 100 K. © 1983 The American Physical Society.