The earlier developed molecular dynamics approach is applied to the investigation of porosity and surface structure of thin films obtained under different deposition conditions. The empirical Monte-Carlo simulation procedure is developed and applied for the search of pores in silicon dioxide thin films. The pores distribution depending on the thickness of growing films and porosity dependence on substrate temperature and deposition energy are studied. It is revealed that the dimensions of pores increase with the decrease of deposition energy. The growth of substrate temperature from 300 K to 500 K results in the increase of porosity in the case of high-energy deposition and in the decrease of porosity in the case of low-energy deposition. It is found that in the case of high-energy deposition film structural properties vary insignificantly with the variation of energy distribution of deposited atoms providing that the average energy of deposited atoms is constant.
The previously developed full-atomistic approach to the thin film growth simulation is applied for the
investigation of the dependence of silicon dioxide films properties on deposition conditions. It is shown that the surface
roughness and porosity are essentially reduced with the growth of energy of deposited silicon atoms. The growth of
energy from 0.1 eV to 10 eV results in the increase of the film density for 0.2 - 0.4 g/cm3 and of the refractive index for
0.04-0.08. The compressive stress in films structures is observed for all deposition conditions. Absolute values of the
stress tensor components increase with the growth of e energy of deposited atoms. The increase of the substrate
temperature results in smoothing of the density profiles of the deposited films.
A new method for supercomputer atomistic modeling of the ion beam sputtering process is presented allowing atomistic modeling of the systems consisting of 106 – 108 atoms. Deposition process is organized as a sequence of molecular dynamic cycles in which deposited atoms interact with the substrate with earlier deposited atoms and form new chemical bonds. The method is applied to the modeling of SiO2 thin optical films. For interatomic potential energy calculation the original DESIL force field with high computational efficiency has been developed. Atomistic modeling of the deposition processes with different Si atom energies is performed for the films with thicknesses up to 30 nm (about one million deposited atoms). Dependence of thin film density on film thickness is investigated. It is found that film densities depend on the energy of sputtered atoms and exceed the density of fused silica substrate by 0.1-0.2 g/cm3. In all experiments interface layers with the thicknesses of about 1-2 nm between thin film and substrate are observed.