Observation of multiple silicon dangling bond configurations in silicon nitride

We show that silicon dangling bonds with different nearest-neighbor configurations and energy levels can be resolved by electron spin resonance (ESR) in silicon nitride. Using an in situ bias technique on large-area metal-nitride-silicon structures, we demonstrate that the ESR line in Si-rich nitride consists of an inhomogeneous distribution of discrete components at different g values. We show that trapping of holes occurs at a site with a g value of 2.0052 corresponding to a pure Si environment, while electron trapping occurs at a site with a g value of 2.0028, corresponding to a pure N environment.