Identification of a paramagnetic recombination center in silicon/silicon-dioxide interface

A paramagnetic recombination center having an orthorhombic symmetry with g[110]= 2.0095(2), g[001]= 2.0038(2), and g [̄110]= 2.0029(2) is found at the interface between silicon and native oxide. The center is referred to P _m center and observed by a spin dependent recombination based electron paramagnetic resonance detection that has the sensitivity of ∼10 ¹¹ spins/cm ². The employment of an isotopically enriched ²⁸Si sample with the concentration of ²⁹Si nuclear spins reduced to 0.017% leads to narrowing of the resonance line. This narrowing is the key for the accurate determination of the angular dependence of the g-factor.