Interstitial nitrogen induced by low-energy ion beam nitridation of AIII–BV semiconductor surfaces

Abstract

The nitridation of GaAs, InAs, and InSb by low-energy N2+ ion bombardment at room temperature was studied by near-edge x-ray absorption fine structure (NEXAFS) and x-ray photoelectron spectroscopy measurements. The formation of thin surface nitride layers, consisting mostly of GaN or InN but also containing minor amounts of mixed nitrides, was observed. Besides the nitride-related features, sharp peaks in the NEXAFS due to π* resonance at 401.0 eV and correlated peaks at 403.8 eV in N 1s core level spectra were detected. Both spectral features could be assigned to the presence of interstitial nitrogen, most likely molecular nitrogen. It was found that the amount of interstitial nitrogen in the surface layer strongly depends on the AIII–BV semiconductor system and may be affected by modification of the conditions during low energy ion bombardment.