AVS 49th International Symposium
    Electronic Materials and Devices Tuesday Sessions
       Session EL+SC-TuA

Paper EL+SC-TuA2
Scanning Tunneling Microscopy Imaging of Charged Defects on Clean Si(100)-(2x1)

Tuesday, November 5, 2002, 2:20 pm, Room C-107

Session: Semiconductor Characterization
Presenter: G.W. Brown, Los Alamos National Laboratory
Authors: G.W. Brown, Los Alamos National Laboratory
H. Grube, Los Alamos National Laboratory
M.E. Hawley, Los Alamos National Laboratory
S.R. Schofield, University of New South Wales, Australia
N.J. Curson, University of New South Wales, Australia
M.Y. Simmons, University of New South Wales, Australia
R.G. Clark, University of New South Wales, Australia
Correspondent: Click to Email
We have used scanning tunneling microscopy (STM) to image charged defects on the clean Si(100)-(2x1) surface. In the absence of "C"-type defects, band bending can occur during STM imaging, allowing near surface charge to influence the state density contributing to the tunnel current. As in the case of cleavage faces of III-V semiconductor crystals, the charge-induced band bending produces long range enhancements superimposed on the periodic surface lattice. We observe this in empty-state STM images taken on n-type Si(100). No band bending signature is seen in the filled-state images. This can be understood by considering the band structure at the surface, which has surface states within the gap. The charged defects observed in this work are of the types commonly observed in clean Si(100)-(2x1) STM studies, however, not all defects of a given type appear charged. This would indicate subtle differences in defect structure or the influence of impurities. This work demonstrates the ability to observe charged features on the clean Si(100) surface, which will be important for current and future research focussed on producing atomic scale electronic structures. Predictions for signatures on p-type material will also be made.