Activation energy for fluorine transport in amorphous silicon

The transport of ion-implanted F in amorphous Si is studied using secondary ion mass spectroscopy and transmission electron microscopy. Significant redistribution of F is observed at temperatures in the range 600-700 degrees C. The measured F depth profiles are modeled using a simple Gaussian solution to the diffusion equation, and the diffusion coefficient is deduced at each temperature. An activation energy of 2.2 eV +/- 0.4 eV for F transport is extracted from an Arrhenius plot of the diffusion coefficients. It is shown that the F transport is influenced by implantation-induced defects. (C) 1999 American Institute of Physics. [S0003-6951(99)03249-0].