Schottky contact formation on polar and non-polar AlN
Abstract
The interfaces of m- and c-plane AlN with metals of different work functions and electro-negativities were characterized and the Schottky barrier heights were measured. The Schottky barrier height was determined by measuring the valence band maximum (VBM) with respect to the Fermi level at the surface (interface) before (after) metallization. VBM determination included accurate modeling and curve fitting of density of states at the valence band edge with the XPS data. The experimental behavior of the barrier heights could not be explained by the Schottky-Mott model and was modeled using InterFace-Induced Gap States (IFIGS). A slope parameter (SX) was used to incorporate the density of surface states and is a measure of Fermi level pinning. The experimental barriers followed theoretical predictions with a barrier height at the surface Fermi level (Charge neutrality level (CNL)) of ∼2.1 eV (∼2.7 eV) on m-plane (c-plane) and SX ∼ 0.36 eV/Miedema unit. Slope parameter much lower than 0.86 implied a surface/interface states dominated behavior with significant Fermi level pinning and the measured barrier heights were close to the CNL. Titanium and zirconium provided the lowest barriers (1.6 eV) with gold providing the highest (2.3 eV) among the metals analyzed on m-plane. It was consistently found that barrier heights decreased from metalmore »
- Authors:
- Publication Date:
- Sponsoring Org.:
- USDOE Advanced Research Projects Agency - Energy (ARPA-E)
- OSTI Identifier:
- 1420474
- Grant/Contract Number:
- AR0000299
- Resource Type:
- Publisher's Accepted Manuscript
- Journal Name:
- Journal of Applied Physics
- Additional Journal Information:
- Journal Name: Journal of Applied Physics Journal Volume: 116 Journal Issue: 19; Journal ID: ISSN 0021-8979
- Publisher:
- American Institute of Physics
- Country of Publication:
- United States
- Language:
- English
Citation Formats
Reddy, Pramod, Bryan, Isaac, Bryan, Zachary, Tweedie, James, Kirste, Ronny, Collazo, Ramon, and Sitar, Zlatko. Schottky contact formation on polar and non-polar AlN. United States: N. p., 2014.
Web. doi:10.1063/1.4901954.
Reddy, Pramod, Bryan, Isaac, Bryan, Zachary, Tweedie, James, Kirste, Ronny, Collazo, Ramon, & Sitar, Zlatko. Schottky contact formation on polar and non-polar AlN. United States. https://doi.org/10.1063/1.4901954
Reddy, Pramod, Bryan, Isaac, Bryan, Zachary, Tweedie, James, Kirste, Ronny, Collazo, Ramon, and Sitar, Zlatko. Tue .
"Schottky contact formation on polar and non-polar AlN". United States. https://doi.org/10.1063/1.4901954.
@article{osti_1420474,
title = {Schottky contact formation on polar and non-polar AlN},
author = {Reddy, Pramod and Bryan, Isaac and Bryan, Zachary and Tweedie, James and Kirste, Ronny and Collazo, Ramon and Sitar, Zlatko},
abstractNote = {The interfaces of m- and c-plane AlN with metals of different work functions and electro-negativities were characterized and the Schottky barrier heights were measured. The Schottky barrier height was determined by measuring the valence band maximum (VBM) with respect to the Fermi level at the surface (interface) before (after) metallization. VBM determination included accurate modeling and curve fitting of density of states at the valence band edge with the XPS data. The experimental behavior of the barrier heights could not be explained by the Schottky-Mott model and was modeled using InterFace-Induced Gap States (IFIGS). A slope parameter (SX) was used to incorporate the density of surface states and is a measure of Fermi level pinning. The experimental barriers followed theoretical predictions with a barrier height at the surface Fermi level (Charge neutrality level (CNL)) of ∼2.1 eV (∼2.7 eV) on m-plane (c-plane) and SX ∼ 0.36 eV/Miedema unit. Slope parameter much lower than 0.86 implied a surface/interface states dominated behavior with significant Fermi level pinning and the measured barrier heights were close to the CNL. Titanium and zirconium provided the lowest barriers (1.6 eV) with gold providing the highest (2.3 eV) among the metals analyzed on m-plane. It was consistently found that barrier heights decreased from metal polar to non-polar surfaces, in general, due to an increasing CNL. The data indicated that charged IFIGS compensate spontaneous polarization charge. These barrier height and slope parameter measurements provided essential information for designing Schottky diodes and other contact-based devices on AlN.},
doi = {10.1063/1.4901954},
journal = {Journal of Applied Physics},
number = 19,
volume = 116,
place = {United States},
year = {Tue Nov 18 00:00:00 EST 2014},
month = {Tue Nov 18 00:00:00 EST 2014}
}
https://doi.org/10.1063/1.4901954
Web of Science
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