Study of Ion-implanted InSb1-xNx Alloys using Secondary Ion Mass Spectroscopy

Due to the band anti-crossing effect by the high-lying nitrogen (N) resonant state, the InSbN alloys show markedly smaller energy band gap. This, together with their long Auger life, makes the alloys the best candidate for long wavelength infrared. We have fabricated a set of InSbN alloys by directly nitrogen implantation into the InSb substrate and characterize them with various facilities after annealing at different temperatures for different periods of time. The secondary ion mass spectrometry indicates that nitrogen atoms in the InSbN alloys are not stable but diffuse significantly. The projected range R_p in the Fick´s second law is modified to be R_p = partt, where part is a constant value which depends on the material condition and the annealing temperature. The diffusion coefficient is determined by fitting the concentration profiles and it can be described by an exponential relation with a constant D₀ of 10^-10 cm²/m and an activation energy of 0.55 eV, indicating an interstitial dominant diffusion process. A dominant tendency for surface nitrogen build-up was observed.