AVS 46th International Symposium
    Surface Science Division Wednesday Sessions
       Session SS3+NS-WeA

Paper SS3+NS-WeA10
TiN(001) Epitaxy: An in-situ Temperature-Dependent STM and Level-Set Modeling Study

Wednesday, October 27, 1999, 5:00 pm, Room 604

Session: Islands, Clusters, and Steps
Presenter: P. Desjardins, University of Illinois, Urbana
Authors: S. Kodambaka, University of Illinois, Urbana
P. Desjardins, University of Illinois, Urbana
A. Vailionis, University of Illinois, Urbana
I. Petrov, University of Illinois, Urbana
J.E. Greene, University of Illinois, Urbana
D. Chopp, Northwestern University
Correspondent: Click to Email
We have used in-situ temperature-dependent STM measurements during deposition and post-annealing combined with modeling to provide atomic-scale insights into surface morphological evolution during TiN growth. Epitaxial TiN(001) layers were grown by reactive evaporation onto MgO(001) at 700-950 @super o@C. Partial TiN monolayers (0.1-0.4 ML) were then deposited and in-situ high-temperature STM used to follow the coarsening and decay kinetics of single and multiple islands (Ostwald ripening) on flat terraces and in single-atom deep vacancy terraces. From these results, combined with finite-element solutions of the Gibbs-Thompson and diffusion equations, we obtain the activation energy for surface diffusion, the Ehrlich barrier energy, and the island line tension. We have also derived and implemented a level-set method for simulating the dynamics of island decay on time scales not accessible to experiment. Level-set methods are numerical techniques for computing the position of propagating fronts that can easily handle topographical changes as well as singularities including corner and cusp development. Our model includes geometry-dependent surface and edge diffusion, step-edge dynamics, and attachment/detachment rates. We compare our numerical results to in-situ STM time-sequence experiments under the same conditions. The results of the level-set calculations serve as a basis for a robust quantitative and predictive model for both microstructural and surface morphological evolution as a function of deposition conditions during polycrystalline TiN growth.