Molecular Dynamics Simulation of Thin Film Growth with Energetic Atoms

Abstract

Thin Film Deposition With Energetic AtomsHyperthermal atoms are deposited upon a substrate in thin film deposition processes. Even when the atoms in the vapor phase are not intentionally accelerated to the substrate, the vapor phase atoms are attracted to the substrate surface with a potential of a few electron volts (eV) because of the interaction between the incoming atom and the substrate. Some deposition processes such as ion beam assisted deposition(IBAD), ion beam deposition (IBD), sputter deposition(S), and plasma enhanced chemical vapor deposition (PECVD)result in ions striking the substrate with energies from 10 to over 100 eV as shown in figure 1[1].Research has demonstrated that energetic incident atoms can increase the density [2], modify the microstructure [3], chemistry [4], and stress [5] ofthin films. Several examples where energetic deposition techniques are known to affect the physical properties are in the deposition of multilayered metals and in the low temperature epitaxial growth of Si. Multilayered metals such as CrfFe and Co/Cu have a giant magnetoresistance (GMR) effect that is a result of changes in scattering of electrons from interfaces as a magnetic field is applied to the multilayer [6,7]. Fullerton and coworkers have shown that the condition and character of the interface is critical to the GMR effect [8], and that the character of the interface can be modified by utilizing energetic incident atoms. In semiconductor systems it is desired to grow epitaxial Si at low temperatures where diffusion will not significantly mix the layers of doped semiconductors, insulators or metals that have previously been created. It has been observed that if energetic Si atoms are deposited at 400°C rather than thermal energy 283 Y. Pauleau (ed.), Chemical Physics of Thin Film Deposition Processes for