THE CARRIER-RECOMBINATION BEHAVIOR AND ANNEALING PROPERTIES OF RADIATION- INDUCED RECOMBINATION CENTERS IN GERMANIUM

Carrier recombination and annealing of radioinduced recombination centers were investigated for both n- and ptype Ge. The experimental results are explained by a model in which recombination occurs at 0.36 ev above the valence band in gamma -irradiated, n-type Ge; the position of this level is shifted slightly downward for neutron-irradiated Ge. Trapping levels occur in As-doped Ge (at 0.17 ev above the valence band) which are not present in Sb-doped Ge. For p-type Ge, an energy level present in unirradiated Ge acts as a trapping center. A value for the electron capture cross section of n-type Ge is derived: 7 x 10/ sup -//sup 1//sup 9/ cm/sup 2/. The annealing properties of Sb- and As-doped Ge are very different. A model for the annealing results is given in which irradiation produces three major types of defects: interstitials, vacancies, and vacancy-interstitial pairs. The properties of each defect type are described. Association of vacancies with doping atoms is discussed. (D.L.C.