AVS 53rd International Symposium
    Plasma Science and Technology Thursday Sessions
       Session PS2-ThA

Invited Paper PS2-ThA1
A Generic Framework of Surface Kinetics Modeling for Plasma-Surface Interactions

Thursday, November 16, 2006, 2:00 pm, Room 2011

Session: Plasma Modeling
Presenter: H.H. Sawin, Massachusetts Institute of Technology
Authors: H.H. Sawin, Massachusetts Institute of Technology
B. Bai, Massachusetts Institute of Technology
Correspondent: Click to Email
A generic surface kinetics model was developed to model the plasma surface kinetics of both etching and deposition processes. The model is based on the translation of a mixed-layer at the substrate surface during plasma processing that is mixed by ion bombardment. This layer translates into the substrate when more material is removed than deposited (etching) and away from the substrate when the net flux is positive. The kinetics of the etching and deposition are based on the assumption that the surface is well mixed by ion bombardment; therefore, the number of any given moiety can be computed based on the elemental composition of the layer. In addition, vacancy species within this layer are also computed. Ion induced etching and sputter removal of surface species are then readily modeled based upon the moiety concentrations. Incorporation of neutrals is based on the concentration of the dangling bonds, as calculated from vacancy species. All major etching characteristics can be explained using this generic modeling approach, including the dependence of the etching yield on the neutral to ion flux ratio, on the neutral composition, on the ion composition, on the ion energy, and on the ion incident angle. The etching processes of silicon in chlorine and bromine plasmas were used as examples and good agreement between experimental results and model prediction were observed. This modeling approach is extremely fast in development and application while capturing all major etching behaviors. Furthermore, the kinetic coefficients determined by this model are readily converted into the probabilities needed for dynamic Monte Carlo 3-D profile simulators.