Hydrogen and Pb defects at the (111)Si-SiO2 interface:: An ab initio cluster study

Employing ab initio density functional methods and atomistic cluster models, we investigate the properties of P-b defects and their interactions with hydrogen at the (111)Si-SiO2 interface. Our calculated hyperfine parameters agree quantitatively with experiments indicating that the P-b defect is a silicon dangling bond at the silicon side of the interface. We calculate the local minimum energy structures for one and two hydrogen atoms interacting with the P-b defect. From these calculations, we derive reaction energies for H-2 adsorption and H desorption. Comparing our results to experimentally derived activation barriers, we suggest different atomistic mechanisms for the observed reactions. [S0163-1829(99)05228-5].