Electroactive complex in thermally treated Ge-Si 〈Cu, Al〉 crystals

Abstract

It is shown by Hall measurements that quenching complexly doped Ge1 − x Si x 〈Cu, Al〉 (0 ≤ x ≤ 0.20) crystals from 1050–1080 K leads to the formation of additional electroactive acceptor centers in them. The activation energy of these centers increases linearly with an increase in the silicon content in the crystal and is described by the relation E k x = (52 + 320x) meV. Annealing these crystals at 550–570 K removes the additional acceptor levels. It is established that the most likely model for the additional electroactive centers is a pair composed of substituent copper and aluminum atoms (Cu s Al s ) or interstitial copper and substituent aluminum atoms (Cu i Al s ). It is shown that the generation of additional deep acceptor levels must be taken into account when using the method of precise doping of Ge1 − x Si x 〈Al〉 crystals with copper.