Electron paramagnetic resonance of a nitrogen-related centre in electron irradiated silicon

The observation by electron paramagnetic resonance of a centre related to nitrogen as an impurity in silicon is reported. While all previously reported nitrogen-related centres in silicon were produced by nitrogen implantation, the present centre is observed after electron irridiation of aluminium-doped silicon at low temperatures. We tentatively identify the observed spectrum, labeled Si-NL26, with neutral interstitial nitrogen. Possible models for the incorporation of nitrogen in silicon, before the irradiation, after the irradiation and after thermal anneal, are discussed.