Heterolytic dissociation under hot-electron bombardment of the silanic bond at the Si-SiO2 interface

An atomistic model is proposed to account for the threshold-voltage instability of mos transistors under hot-electron bombardment. High-level density-functional-theory calculations for a set of model molecules simulating the Si-SiO₂ interface show that in the presence of one adsorbed water molecule the diradical center (resulting from the homolytic cleavage by hot-electron impact of the silanic bond at the hydrogen-passivated interface trap) evolves spontaneously to the formation of a positively charged defect at the oxide side of the Si-SiO₂ interface. Received: 10 January 2001 / Accepted: 19 June 2001 / Published online: 30 August 2001