Smcon diffusion at po~ycrystamne-SilGaAs interfaces

Pollycrystalline-Si/GaAs interfaces have been prepared by depositing hydrogenated amorphous Si (a-Si:H) onto GaAs in a silane plasma at 450°C and annealing at temperatures between 600 and 1020 dc. Rutherford backscattering, secondary ion mass spectroscopy, and transmission electron microscopy show that the resulting polycrystaHine-SilGaAs interface is metaBurgically stable when the Si is und.oped while significant interdiffusion occurs when 12 at. % As is added to the Si. The data are consistent with the Greiner/Gibbons theory [Appl. Phys. Lett. 44, 750 (1984)] that high concentrations of Si diffuse in GaAs in the form of Si-Si substitutional pairs via Ga and As vacancies.