AVS 53rd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThP

Paper EM-ThP16
Bonding Geometries of In@sub 2@O on InAs(001)-(4x2)

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Electronic Materials and Processing Poster Session
Presenter: J. Shen, University of California, San Diego
Authors: J. Shen, University of California, San Diego
D.L. Winn, University of California, San Diego
N.M. Santagata, University of California, San Diego
A.C. Kummel, University of California, San Diego
Correspondent: Click to Email
The key to fabricating a high mobility MOSFET is forming an electrically passive oxide-semiconductor interface on a very high molibity semiconductor. The absence of As-As dimers makes the InAs(001)-(4x2) surface ideal for gate oxide deposition, since the surface should not readily react with deposited oxides. Scanning tunneling microscopy (STM) and density functional theory (DFT) were used to definitively identify the InAs(001)-(4x2) reconstruction along with ascertaining how In@sub 2@O adsorbates bond onto the clean surface. The clean surface consists of single In-In dimers that run in the [110] direction. Between the row dimers is a trough region that contains 2 additional In-In dimers. After the InAs(001)-(4x2) reconstruction was identified, In@sub 2@O was deposited onto the clean surface using MBE. The lowest coverage In@sub 2@O adsorption site was identified as an In atom from In@sub 2@O bonding to a tricoordinated As atoms at the edge of the row. When this occurs, it causes the second In atom in In@sub 2@O to bond nonspecifically in the trough region. Evan at low coverage (20% monolayer (ML)), the In@sub 2@O adsorbates formed islands that are elongated in the [110] direction. Prior to all the first layer sites being occupied with In@sub 2@O molecules, second layer growth was observed on the islands. This was attributed to the In atom, in the In@sub 2@O molecule, that protruded into the trough region being highly reactive. Most importantly, the In@sub 2@O adsorbates never causes the abstraction of any surface atoms on the InAs(001)-(4x2) surface. This is consistent with the formation of a smooth interface between the oxide and the semiconductor. STS measurements are being performed to determine the electronic properties of the interface.