Theory of charge-state splittings of deep levels

Abstract

The Green's-function method, with an empirical tight-binding basis, is used to determine the deep levels of the singly ionized and neutral impurities S, Se, and Te in Si. The impurity potentials are determined self-consistently. The resulting theory accounts for the observed charge-state splittings of neutral and singly ionized ${A}_{1}$ deep levels, obtaining, for S, Se, and Te, 0.23, 0.22, and 0.19 eV (to be compared with experimental values of 0.30, 0.29, and 0.21 eV, and with a self-consistent local-density-theory value for S of 0.20).