J. Phys. III France 6 (1996) 1691-1696
Electrical Properties of Silver Impurities and their Annealing Behaviour in p-Type Fz SiliconG.A. Adegboyega1, L. Passari2, M.A. Butturi2, A. Poggi3 and E. Suzi3
1 Department of Electronic and Electrical Enginneering, Obafemi Awolowo University, Ile-Ife, Nigeria
2 Dipartimento di Fisica-Universita, Via Paradiso 12, 44100 Ferrara, Italy
3 CNR-Istituto LAMEL, Via P. Gobetti 101, 40129 Bologna, Italy
(Received 6 February 1996, revised 26 July 1996, accepted 13 September 1996)
The electrical activity of silver as well as its annealing properties in cm p-type Fz silicon substrate are studied by means of the four-point probe and minority carrier lifetime measurements. Silver atom concentration in the range 10 14 to 10 15 cm -3 consistently showed a donor type behaviour in the material and its presence led to a reduction of up to two orders of magnitude in the lifetime of minority carriers by the formation of deep-level traps. Isochronal annealing of silver contaminated specimens showed some gettering of the Ag impurities with resulting temperature dependent changes in the resistivity as well as the minority carrier lifetime values. Analysis of our results shows that a large fraction of the silver impurity atoms present forms the deep level defects and both the deep- and donor-levels appear to originate from the same source.
© Les Editions de Physique 1996