Atomic and electronic structures of the N substitutional impurity in Si

Abstract

A first-principles calculation based on the local-density approximation and supercell model is performed for the N substitutional impurity in Si. Good agreement between theory and electron spin resonance (ESR) experiment is obtained: the stable atomic geometry is found to have the ${C}_{3v}$ symmetry as indicated by ESR studies; the calculated energy difference between ${C}_{3v}$ and ${T}_{d}$ is less than 0.1 eV, while the experimental value is 0.073 eV; the calculated highest occupied level mainly consists of the Si dangling bond. The ${C}_{3v}$ structures for P and As impurities are found to be unstable for the neutral and negative charge states. The reason for the difference between the N and other group-V atoms is discussed.