Passivation and dissociation of Pb-type defects at a-SiO2/Si interface.

It is well known that in the process of thermal oxidation of silicon, there are Pb-type defects at amorphous silicon dioxide/silicon (a-SiO2/Si) interface due to strain. These defects have a very important impact on the performance and reliability of semiconductor devices. In the process of passivation, hydrogen is usually used to inactivate Pb-type defects by the reaction Pb + H2 → PbH + H. At the same time, PbH centers dissociate according to the chemical reaction Pb H → Pb +H. Therefore, it is of great significance to study the balance of the passivation and dissociation. In this work, the reaction mechanisms of passivation and dissociation of the Pb-type defects are investigated by first-principles calculations. The reaction rates of the passivation and dissociation are calculated by the climbing image-nudged elastic band (CI-NEB) method and harmonic transition state theory (HTST). By coupling the rate equations of the passivation and dissociation reactions, the equilibrium density ratio of the saturated interfacial dangling bonds and interfacial defects (Pb, Pb0, and Pb1) at different temperatures is calculated. [ABSTRACT FROM AUTHOR]