THEORETICAL CALCULATION OF THE ELECTRON-CAPTURE CROSS-SECTION DUE TO A DANGLING BOND AT THE SI(111)-SIO2 INTERFACE

Using an accurate formulation of carrier capture assisted by phonons [D. Goguenheim and M. Lannoo, J. Appl. Phys. 68, 1059 (1990)], we perform a complete theoretical calculation of the electron-capture cross section a due to a dangling bond at the Si(111)-SiO2 interface (the so-called P(b0) center). In order to calculate electron-phonon coupling terms, we describe this defect with a tight-binding cluster model in which, in spite of its simplicity, the interatomic forces found on the trivalent silicon atom for the three charge states of the dangling bond reproduce the results of more developed models. This allows the calculation of the coupling parameters with a good accuracy. Sums over phonon normal modes are evaluated using Green's-function techniques. Finally, we derive numerical values of a for the P(b0) center, study its dependence on temperature, and compare our results with experimental values.