AVS 50th International Symposium
    Surface Science Thursday Sessions
       Session SS1-ThM

Paper SS1-ThM3
Length Scale Dependence of Evolution of Corrugations During Sublimation from Patterned Vicinal Si(111) Surfaces*

Thursday, November 6, 2003, 9:00 am, Room 310

Session: Patterned Growth and Etching of Semiconductors
Presenter: R.J. Phaneuf, University of Maryland
Authors: T. Kwon, University of Maryland
H.C. Kan, University of Maryland
R.J. Phaneuf, University of Maryland
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We describe the results of a combinatorial approach toward controlling the evolution of topography during sublimation from silicon. Arrays of lithographically-patterned cylindrical pits on vicinal Si(111) surfaces interfere with the motion of "straight" steps at temperatures near 1200C. On each substrate, pit diameters are varied from 0.7 microns to 8 microns, with the pit-spacing equal to twice the diameter. Within this range, a critical length scale is found, above which straight steps wrap around pits, leaving a pronounced corrugation within the surface plane, but beneath which the evolution is quickly to straight step bunches, with a pronounced corrugation perpendicular to the surface plane. In the simplest model, this critical length scale is set by the competition between the sublimation induced spreading pressure on the steps and their intrinsic stiffness. Preliminary observations on vicinal Si(111) surfaces also indicate the importance of step-step interactions in the evolution of the topography, with a pronounced inward relaxation of the pit wall on the "uphill" side, and an inward bowing of otherwise straight steps on the "downhill" side. *Work supported by the Laboratory for Physical Sciences and an NSF-MRSEC.