Atomic Lithography: Forcing Epitaxial Growth Using X-ray Standing Waves
Abstract
Over the last year we made considerable progress towards demonstrating an effect of an x-ray standing wave on the deposition of a Ge film. In the presence of the standing wave we observed a change in the film morphology of Ge grown on Si(111) below the temperature needed for epitaxial growth. Beam-exposed regions appear flat and resemble the Si(111) substrate, while unexposed regions are rough and display polycrystalline morphology similar to that seen for Ge growth on amorphous substrates. Consistent with our expectations, at higher deposition temperatures the effect is no longer observable. Similarly, for the deposition conditions we have been able to investigate to date on amorphous substrates we do not see any difference in the morphology between beam-on and beam-off regions. This is consistent with an effect arising from a weak coupling between the standing wave field and the Ge atoms on the surface which, at the x-ray intensities we can achieve without modifications to our optical geometry, is insufficient to modify the growth by itself, but when coupled with the periodic potential due to the substrate can push the Ge atoms into a new stable configuration. We found this to be very promising development toward our ultimate goal of atomic lithography. Below, we discuss in more detail the experimental approach to these recent standing wave depositions and their results.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 06, 2002
- Accession Number
- ADA408986
Entities
People
- Charles M. Falco
Organizations
- University of Arizona