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Title: Au and Al Schottky barrier formation on GaAs (100) surfaces prepared by thermal desorption of a protective arsenic coating

Abstract

Photoelectron spectroscopy has been used as a tool to investigate the initial stages of Schottky barrier formation on GaAs (100) surfaces. This is a popular technique that has been used by many researchers in the past to measure the band bending (or shift) of the valence band and conduction band (a measure of the Schottky barrier shift), while the Fermi level remains fixed at the system ground (i.e., the ground of the spectrometer). Metal deposition on a semiconductor surface can alter the Schottky barrier at the surface and pin the Fermi level near the middle of the energy gap. Extremely clean and crystallographically perfect surfaces are required in this study. Toward this end, a method of protecting the GaAs surface was employed which consists of capping the GaAs surface with a layer of As. Upon introduction into the high vacuum system the As is thermally desorbed, revealing a pure GaAs surface. Our work was motivated by a previous study (Brillson et al) on similarly capped specimens, which suggested that metal overlayers do not pin the Schottky barrier in GaAs. Barrier heights varied by as much as 0.75 eV between Al and Au overlayers. This large energy range is a strikingmore » result in view of the fact that a considerable number of prior studies on both (110) and (100) surfaces have found that all metals will pin within a narrow (0.25 eV) range at midgap. We repeated the measurements of Brillson on the identically doped samples used in their study using two extreme range metals of Au and Al as overlayers. We found that the barrier height measurements on low doped n-type samples used in this work and in the previous work are affected by photovoltaic effects, even at room temperature. This was determined from taking spectra at a number of temperatures between 20 K and room temperature and looking for shifts. 16 refs., 7 figs.« less

Authors:
; ; ; ; ;  [1];  [2]; ;  [3]
  1. Stanford Univ., CA (United States). Stanford Electronics Labs.
  2. Los Alamos National Lab., NM (United States)
  3. International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center
Publication Date:
Research Org.:
Los Alamos National Lab., NM (United States)
Sponsoring Org.:
USDOE; USDOD; USDOE, Washington, DC (United States); Department of Defense, Washington, DC (United States)
OSTI Identifier:
6187096
Report Number(s):
LA-UR-91-3257; CONF-910115-1
ON: DE92002456
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: 18. annual conference on physics and chemistry of semiconductor interfaces and topical conference on silicon based heterostructures, Long Beach, CA (United States), 29 Jan - 1 Feb 1991
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING; ALUMINIUM; DEPOSITION; ARSENIC; COATINGS; DESORPTION; GOLD; GALLIUM ARSENIDES; PHOTOELECTRON SPECTROSCOPY; PHOTOVOLTAIC EFFECT; SCHOTTKY BARRIER DIODES; SURFACES; ARSENIC COMPOUNDS; ARSENIDES; ELECTRON SPECTROSCOPY; ELEMENTS; GALLIUM COMPOUNDS; METALS; PHOTOELECTROMAGNETIC EFFECTS; PNICTIDES; SEMICONDUCTOR DEVICES; SEMICONDUCTOR DIODES; SEMIMETALS; SPECTROSCOPY; TRANSITION ELEMENTS; 360601* - Other Materials- Preparation & Manufacture; 426000 - Engineering- Components, Electron Devices & Circuits- (1990-)

Citation Formats

Spindt, C J, Yamada, M, Meissner, P L, Miyano, K E, Herrera, A, Spicer, W E, Arko, A J, Woodall, J M, and Pettit, G D. Au and Al Schottky barrier formation on GaAs (100) surfaces prepared by thermal desorption of a protective arsenic coating. United States: N. p., 1991. Web.
Spindt, C J, Yamada, M, Meissner, P L, Miyano, K E, Herrera, A, Spicer, W E, Arko, A J, Woodall, J M, & Pettit, G D. Au and Al Schottky barrier formation on GaAs (100) surfaces prepared by thermal desorption of a protective arsenic coating. United States.
Spindt, C J, Yamada, M, Meissner, P L, Miyano, K E, Herrera, A, Spicer, W E, Arko, A J, Woodall, J M, and Pettit, G D. Tue . "Au and Al Schottky barrier formation on GaAs (100) surfaces prepared by thermal desorption of a protective arsenic coating". United States. https://www.osti.gov/servlets/purl/6187096.
@article{osti_6187096,
title = {Au and Al Schottky barrier formation on GaAs (100) surfaces prepared by thermal desorption of a protective arsenic coating},
author = {Spindt, C J and Yamada, M and Meissner, P L and Miyano, K E and Herrera, A and Spicer, W E and Arko, A J and Woodall, J M and Pettit, G D},
abstractNote = {Photoelectron spectroscopy has been used as a tool to investigate the initial stages of Schottky barrier formation on GaAs (100) surfaces. This is a popular technique that has been used by many researchers in the past to measure the band bending (or shift) of the valence band and conduction band (a measure of the Schottky barrier shift), while the Fermi level remains fixed at the system ground (i.e., the ground of the spectrometer). Metal deposition on a semiconductor surface can alter the Schottky barrier at the surface and pin the Fermi level near the middle of the energy gap. Extremely clean and crystallographically perfect surfaces are required in this study. Toward this end, a method of protecting the GaAs surface was employed which consists of capping the GaAs surface with a layer of As. Upon introduction into the high vacuum system the As is thermally desorbed, revealing a pure GaAs surface. Our work was motivated by a previous study (Brillson et al) on similarly capped specimens, which suggested that metal overlayers do not pin the Schottky barrier in GaAs. Barrier heights varied by as much as 0.75 eV between Al and Au overlayers. This large energy range is a striking result in view of the fact that a considerable number of prior studies on both (110) and (100) surfaces have found that all metals will pin within a narrow (0.25 eV) range at midgap. We repeated the measurements of Brillson on the identically doped samples used in their study using two extreme range metals of Au and Al as overlayers. We found that the barrier height measurements on low doped n-type samples used in this work and in the previous work are affected by photovoltaic effects, even at room temperature. This was determined from taking spectra at a number of temperatures between 20 K and room temperature and looking for shifts. 16 refs., 7 figs.},
doi = {},
url = {https://www.osti.gov/biblio/6187096}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1991},
month = {1}
}

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