RBS simulations studies of SIMOX structure

Abstract

In the paper we present the short description of physical phenomena related to the motion of ion inside the crystal. The form of this description makes it possible and easy to construct the calculation procedures. The final results are the simulation and experimental data for the Si(001)-Si02-Si(001 (SIMOX) structure. The comparison of the results obtained shows that the problem of energy losses of fast ion moving inside such well ordered structure like single crystal is the fundamental one in order to good understand the quality of Si-Si02 interface and its location under the surface of sample. Only for a very thin amorphous layers thickness' and for the energies of incident ion close to the maximum of energy losses the assumption about the linear dependence between the energy loss and the penetration depth is right. If the direction of incidence of ion lies along one of main crystallographic directions the analytical models proposed in literature give results, which are in bad agreement with experimental data. The correct results were, however, obtained using simulation of successive collisions with the nearest atom of crystallographic lattice with impact parameter dependent energy losses and helium ion charge state taken into consideration. This attempt significantly lengthened simulation time but allowed for good reconstruction of the shape of energetic spectra as to show slight perturbations of SIMOX structure.