Hydrogen effect on enhancement of defect reactions in semiconductors: example for silicon and vacancy defects

A model of interaction of the hydrogenated vacancy with silicon interstitia l and different dopants (B, P and As) in crystalline silicon is considered. Quantum chemical calculations show that hydrogenation of the vacancy leads to a decrease of mechanical stresses of the silicon crystalline lattice ne ar vacancy and consequently to a considerable decrease of the energy barrie r height for the interstitial atom incorporation into the vacancy site of t he crystalline lattice. The potential barriers for incorporation of the int erstitial into the site and for leaving the atoms from the site has been ca lculated as a function of hydrogen localization in the vicinity of the vaca ncy (inside and outside of the vacancy), the charge state of hydrogen local ized outside the vacancy (H-0 and H+), and the transport direction ([111], [110] and [100]) of the atoms both in and out of the vacancy. The theory is compared with the experimental results. (C) 2001 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserve d.