Model for NL10 thermal donors formed in annealed oxygen-rich silicon crystals

Electron spin resonance (ESR) studies have shown that NL10 thermal donors are formed in oxygen-rich silicon (Si) crystals after annealing. In initial NL10 formation stage, it has C2v symmetry with the principle g values g[100]=1.99982, g[01̄1]=1.99799, g[011]=1.99946. After annealing, however, we could detect ESR signals with g values close to those of NL10 in nitrogen-doped oxygen-rich Si crystals. The ESR signals corresponded to nitrogen-oxygen complex donors [D(N,O)s]. We studied the similarities between D(N,O)s and NL10 centers with C2v symmetry. We propose a model for NL10 thermal donors that NL10 with C2v symmetry is D(N,O). Our model clearly explains NL10 thermal donors characteristics.