Simulation par la dynamique moléculaire de l'interaction plasma-surface lors de la croissance de couches minces a-

Abstract

The Plasma Enhanced Chemical Vapor Deposition (PECVD) is amongst of the most common methods of thin films elaboration.For the study of a-Si:H thin film growth by PECVD process in RF (13.56 MHz) reactor, we are interested in the interaction of electrons, SiHx (x = 1, 2,3) radicals and H existing in the volume of the plasma with the surface.The radicals interact with the surface according their concentrations in the plasma and their activation energies during chemical reactions on the surface sites.The used plasma is a mixture of silane-hydrogen (SiH4/H2). The gas temperature ranges from300K to 700K. We developed a numerical simulation model using molecular dynamics which based on the (9-3) Lennard-Jones radical-surface interaction potential.This simulation allows calculation of sticking (s), recombination (γ) and reactivity (β) coefficients of radicals at the surface. For the SiH3 radical, the calculated value of βSiH3 is 0.47 at 520K for value of activation energy of H-abstraction by SiH3 radical equal 0.12 eV.