In-Ga intermixing in low-temperature grown GaAs delta doped with In

Bert, N. A., Chaldyshev, V. V., Musikhin, Y. G., Suvorova, A. A., Preobrazhenskii, V. V., Putyato, M. A., Semyagin, B. R. and Werner, P.

Applied Physics Letters 74, (10), pp 1442-1444 (1999)

Low-temperature grown GaAs films with indium delta layers are studied by transmission electron microscopy. The delta layers in the as-grown film are found to be as thick as four monolayers (ML) independently of a nominal In deposit of 0.5 or 1 ML, a thickness which reflects the film surface roughness during the low-temperature growth. A pronounced In-Ga intermixing is observed in the films subjected to 500-700 degrees C isochronal anneals. The In-Ga interdiffusion diffusivity is evaluated. The effective activation energy for In-Ga interdiffusion is found to be 1.1 +/- 0.3 eV which is significantly smaller than a value of 1.93 eV for a stoichiometric GaAs. The difference seems to result from a loss of the gallium vacancy supersaturation upon annealing, and is consistent with an annihilation enthalpy of 0.8 eV. (C) 1999 American Institute of Physics. [S0003-6951(99)00310-1]. [References: 18]

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