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 wi th a buried N doping layer were grown by molecular beam epitaxy and di ffusion annealed between 808 and 880 degrees C in As-rich ambient. Nit rogen distributions determined by secondary ion mass spectroscopy reve al a marked non-Gaussian broadening of the as-grown peak. Computer mod eling yields strong evidence for the kick-out diffusion mechanism invo lving interstitial (N-i) substitutional (N-s) exchange assisted by As interstitials (I-As) This allows us to deduce the I-As-related diffusi on coefficient of As in GaAs. Comparison with existing As tracer diffu sivities points to a substantial contribution of I-As to As diffusion in GaAs. [S0031-9007(98)07428-6].