Theoretical model and computer simulation results of enhanced diffusion of high-temperature implanted aluminum in silicon carbide

The wide-spread use of silicon carbide (SIC) films in the production of microelectronic devices make predictions of the doping profiles during and/or after thermal treatment especially important. A macroscopic kinetic model of enhanced diffusion of aluminum in SiC films during ion bombardment at high temperatures has been considered. The set of equations describing the kinetic model takes into account the generation of V-C and V-Si vacancies during bombardment, migration of mobile species (Aluminum) towards the surface and reactions of Al atoms with V-C and V-Si vacancies, as well as Al evolution from the film. Numerical simulation of the equations have been carried out to obtain the concentration profile of AI implanted into SiC, the special distribution of immobile AI atoms substituting Si and C sites in SiC lattice, mobile Al atoms, and the number of Al atoms which leave the film. The calculations were carried out for the flux of Al ions with the energy of 40 keV and current density 20 mu A/cm(2) to a dose 2 x 10(16) cm(-2) at 1800 degrees C. The calculations have shown that the Al content in SIC at these conditions does not exceed 40%. The calculated profile of Al is in good agreement with the experimental data (A.V. Suvorov, I.O. Usov, V.V. Sokolov, A.A. Suvorova, in: D.B. Poker, D. Ila, Y.-S. Cheng, L.R. Harriot, T.W. Sigmon (Eds.), Ion-Solid Interaction for Materials Modification and Processing, PA, 1996, pp. 239-242). (C) 1998 Elsevier Science B.V. All rights reserved.