AVS 47th International Symposium
    Manufacturing Science and Technology Thursday Sessions
       Session MS-ThM

Paper MS-ThM2
New Physics for Models of Transient Enhanced Diffusion

Thursday, October 5, 2000, 8:40 am, Room 304

Session: Advanced Modeling and Control for IC Manufacturing
Presenter: E.G. Seebauer, University of Illinois, Urbana-Champaign
Authors: M.Y.L. Jung, University of Illinois, Urbana-Champaign
E.G. Seebauer, University of Illinois, Urbana-Champaign
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As device dimensions continue to shrink, the constraints on processing imposed by Mother Nature become ever more stringent. The optimization of chemical kinetics and mass transport is therefore playing an increasingly important role in defining and widening process windows. Here we discuss TCAD modeling of transient-enhanced diffusion (TED) after ion implantation during ultrashallow junction formation by rapid thermal annealing. TED has long been modeled using a large set of reaction-diffusion equations for the dopant, point defects, and extended defects. However, current commercial and public-domain SUPREM-based software mishandles several important aspects of the reaction-diffusion network. For example, many of the diffusivities are inappropriately parameterized. Also, the software lacks a self-consistent, time-dependent treatment of Poisson's equation and therefore miscalculates the electric-field-driven drift of charged defects. There are further problems: even the best TED models neglect important effects of the nearby free surface and of intense illumination. For example, there is no incorporation of near-surface band bending, of changes in charged defect concentration during illumination, or of enhancement of point defect motion though local energy dumping by e-h recombination. This talk outlines how such effects can be incorporated and discusses conditions under which they are likely to be important.