Bratchenko M. Kinetic description and mathematical simulation of ion implantation into crystals

The dissertation deals with the theoretical description of the implantation condi-tions dependency of 1-200 keV ions implantation profiles in crystals. Formulated is the general approach to the problem considered as a joint kinetics of channeling and chaotic motion and described by the bound system of Chapman-Kolmogorov equations. New method of computer simulation studies of ion implantation in crystals has been developed that combines simulation of ion's three-dimensional trajectory with calculation of parameters of its channeling in the nearest axial channel. The dechanneling problem of low energy ions has been solved in the continuous slowing-down approximation. An analytical solution for dechanneling function has been obtained, analyzed qualitatively, and compared with experimental data. The regime of metachanneling has been first introduced which corresponds to the dynamically unstable channeling of ions having specific energy losses reduced with respect to those in an amorphous medium. The expression for the critical angle of metachanneling has been obtained. The phenomenological model of ion implantation profiles in crystals has been developed that improves the quality of the parameterization of experimental data in comparison with that of the standard empirical model. It also opens the possibility of evaluation of kinetic parameters of low-energy ions channeling basing on the experimental data available.