Department: Grad. Program in Materials Science
Sungho Jin | Andrew Kummel
Name: Jian Shen
Email: jimshen @ ucsd.edu
Grad Year: 2008
The key to fabricating a high mobility MOSFET is forming an electrically passive oxide-semiconductor interface on a very high mobility semiconductor. In an effort to identify an unpinned oxide/semiconductor interface on InAs, a detailed study of In2O adsorbed to InAs(001)-(4x2) was performed. Scanning tunneling microscopy (STM) and density functional theory (DFT) were used to ascertaining how In2O adsorbates bond to the clean surface. The lowest coverage In2O adsorption site was identified as an In2O molecule bonding to the edge of the row. Evan at low coverage (20% monolayer (ML)), the In2O adsorbates formed islands that are elongated in the  direction. Prior to all the first layer sites being occupied with In2O molecules, second layer growth was observed on the islands. Most importantly, the In2O adsorbates never cause the abstraction of any surface atoms on the InAs(001)-(4x2) surface and the In2O molecules only occupied specific sites. This is consistent with the formation of a smooth interface between the oxide and the semiconductor.
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