Diffusion Of Nitrogen From A Buried Doping Layer In Gallium Arsenide Revealing The Prominent Role Of As Interstitials

We report the first measurements of N diffusion in GaAs. GaAs films with a buried N doping layer were grown by molecular beam epitaxy and diffusion annealed between 808 and 880 degrees C in As-rich ambient. Nitrogen distributions determined by secondary ion mass spectroscopy reveal a marked non-Gaussian broadening of the as-grown peak. Computer modeling yields strong evidence for the kick-out diffusion mechanism involving interstitial (N-i) substitutional (N-s) exchange assisted by As interstitials (I-As) This allows us to deduce the I-As-related diffusion coefficient of As in GaAs. Comparison with existing As tracer diffusivities points to a substantial contribution of I-As to As diffusion in GaAs. [S0031-9007(98)07428-6].