Effect of rapid thermal annealing on behavior of nitrogen in GaAsN alloys

We report the behavior of nitrogen implanted into GaAs wafer upon annealing in the range of 500 °C to 1000 °C. The SIMS results show out-diffusion of nitrogen and the peaks in the distribution profiles of implanted nitrogen broadening. XPS measurements indicate that the N bonding configuration before annealing is contributed by NAs, interstitial NN and the NAs complex. However, NAs complex disappears completely upon annealing at temperature higher than 700 °C. The spectra and quantitative analysis reveal that a saturation of NAs happens as annealing temperature increases. Before the saturation, the substitional NAs keeps rising, which leads to the elevation of n-type doping level in host. Whereas beyond the saturation, the excess thermal energy beyond saturation triggers the kick-out mechanism and induces dramatic increase in the amount of NN split interstitials, resulting in suppression of the nitrogen out-diffusion during annealing and pining of the Fermi level.

► We study the effect of thermal energy excited by different temperature annealing on the nitrogen distribution and configuration in ion implanted GaAsN.
► We quantitatively analyze the variation of Fermi level influenced by the N configuration.
► A saturation annealing temperature is found for the concentration of substitutional NAs in ion implanted GaAsN.
► Excess thermal energy beyond saturation induces dramatic increase in the amount of NN split interstitials, resulting in suppression of the nitrogen out-diffusion during annealing and pining of the Fermi level.