Halogen-induced modification of silicon surfaces: etching roughening, and step transformations

Butera, Robert E.

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https://hdl.handle.net/2142/16827 Copy

Description

Title

Halogen-induced modification of silicon surfaces: etching roughening, and step transformations

Author(s)

Butera, Robert E.

Issue Date

2010-08-20T17:59:01Z

Director of Research (if dissertation) or Advisor (if thesis)

Weaver, John H.

Doctoral Committee Chair(s)

Weaver, John H.

Committee Member(s)

• Abelson, John R.
• Petrov, Ivan G.
• Rockett, Angus A.

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Scanning Tunneling Microscopy
• Si(100)
• Halogen etching
• Surface Science
• Steps

Abstract

I have combined scanning tunneling microscopy with density functional calculations and Monte Carlo simulations to investigate halogen-induced modifications of Si surfaces, including etching, roughening and step transformations. These investigations have focused on elucidating the atomic-level details associated with the evolution of terrace and step sites on Cl-Si(100)-(2x1) under conditions of halogen supersaturation. I present a novel adsorption mechanism that is accessed upon exposing nearly-saturated Cl-Si(100)-(2x1) to a flux of Cl2, whereby dangling bonds of the nearly-saturated surface mediate the insertion of Cl adsorbates into non-equilibrium adsorption sites. The adsorbates are kinetically trapped within these sites due to energy constraints and lack of available and more favorable adsorption sites. Inserted Cl adsorbates force the surface to evolve along a novel etching pathway at elevated temperature resulting in dimer vacancy formation without the customary Si regrowth features attributed to halogen etching processes. This process is investigated at 700 – 825 K and the reaction mechanism is extracted from analysis of the appropriate rate equations.

Graduation Semester

2010-08

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http://hdl.handle.net/2142/16827

Copyright and License Information

Copyright 2010 Robert E. Butera

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