AVS 49th International Symposium
    Manufacturing Science and Technology Monday Sessions
       Session MS+SE-MoM

Paper MS+SE-MoM6
The Evolution of Single Atomic Steps on vicinal Si(111) in NH@sub 4@F

Monday, November 4, 2002, 10:00 am, Room C-109

Session: In-Situ Monitoring and Metrology for Coating Growth and Manufacturing
Presenter: J. Fu, National Institute of Standards and Technology
Authors: J. Fu, National Institute of Standards and Technology
H. Zhou, University of Maryland
J.A. Kramar, National Institute of Standards and Technology
R. Silver, National Institute of Standards and Technology
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Determining the width of a feature or the scale in a pitch measurement with appropriate accuracy is fundamental for process control in state-of-the-art semiconductor manufacturing. To meet these needs as well as the future measurement and calibration needs of the emerging nanomanufacturing industry, the National Institute of Standards and Technology (NIST) has been pursuing research and development on techniques for the fabrication and measurement of atom-based dimensional standards. The key elements in the development of atom-based standards are the ability to prepare atomically ordered surfaces,and the ability to count the atoms making up the features of interest. One of the most difficult challenges in atom-based metrology has been the fabrication of an appropriate atomic template. Atomically ordered surfaces provide an intrinsic template which have both scale and orthogonality. Using Scanning Probe Microscopy(SPM), We have examined the surface produced by etching several different vicinal Si(111) sample in 40% NH@sub 4@F. In agreement with others, we find that deoxygenation of the etchant generally reduces the number of triangular etch pits. The formation of single atomic steps is evolved from these etch pits. These etch pits undergo nucleation, growth, merging, and corner rounding which can lead to single atomic steps. We also find that for maximum uniformity and minimum root mean square roughness, a certain minimum miscut angle is required. This angle is related to the maximum clear terrace width, which in turn is related to the relative etching rate of the step-edge sites and the terrace sites. The time evolution of the surface-smoothing etching process was also examined.