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Title: Spectroscopic ellipsometry studies of GaN films deposited by reactive rf sputtering of GaAs target

Abstract

GaN films have been deposited by reactive rf sputtering of GaAs target in 100% nitrogen ambient on quartz substrates at different substrate temperatures ranging from room temperature to 700 deg. C. A series of films, from arsenic-rich amorphous to nearly arsenic-free polycrystalline hexagonal GaN, has been obtained. The films have been characterized by phase modulated spectroscopic ellipsometry to obtain the optical parameters, viz., fundamental band gap, refractive index, and extinction coefficient, and to understand their dependence on composition and microstructure. A generalized optical dispersion model has been used to carry out the ellipsometric analysis for amorphous and polycrystalline GaN films and the variation of the optical parameters of the films has been studied as a function of substrate temperature. The refractive index values of polycrystalline films with preferred orientation of crystallites are slightly higher (2.2) compared to those for amorphous and randomly oriented films. The dominantly amorphous GaN film shows a band gap of 3.47 eV, which decreases to 3.37 eV for the strongly c-axis oriented polycrystalline film due to the reduction in amorphous phase content with increase in substrate temperature.

Authors:
; ;  [1]; ;  [2];  [3]
  1. Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)
  2. Department of Physics, Indian Institute of Technology Bombay, Mumbai 400 076 (India)
  3. Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400 076 (India)
Publication Date:
OSTI Identifier:
21137163
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 103; Journal Issue: 8; Other Information: DOI: 10.1063/1.2903443; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AMORPHOUS STATE; ARSENIC; CRYSTAL GROWTH; CRYSTAL STRUCTURE; ELLIPSOMETRY; ENERGY GAP; GALLIUM ARSENIDES; GALLIUM NITRIDES; GRAIN ORIENTATION; NITROGEN; OPTICAL DISPERSION; POLYCRYSTALS; POLYMERS; QUARTZ; REFRACTIVE INDEX; SEMICONDUCTOR MATERIALS; SPUTTERING; SUBSTRATES; TEMPERATURE RANGE 0273-0400 K; THIN FILMS

Citation Formats

Biswas, A, Bhattacharyya, D, Sahoo, N K, Yadav, Brajesh S, Major, S S, and Srinivasa, R S. Spectroscopic ellipsometry studies of GaN films deposited by reactive rf sputtering of GaAs target. United States: N. p., 2008. Web. doi:10.1063/1.2903443.
Biswas, A, Bhattacharyya, D, Sahoo, N K, Yadav, Brajesh S, Major, S S, & Srinivasa, R S. Spectroscopic ellipsometry studies of GaN films deposited by reactive rf sputtering of GaAs target. United States. https://doi.org/10.1063/1.2903443
Biswas, A, Bhattacharyya, D, Sahoo, N K, Yadav, Brajesh S, Major, S S, and Srinivasa, R S. 2008. "Spectroscopic ellipsometry studies of GaN films deposited by reactive rf sputtering of GaAs target". United States. https://doi.org/10.1063/1.2903443.
@article{osti_21137163,
title = {Spectroscopic ellipsometry studies of GaN films deposited by reactive rf sputtering of GaAs target},
author = {Biswas, A and Bhattacharyya, D and Sahoo, N K and Yadav, Brajesh S and Major, S S and Srinivasa, R S},
abstractNote = {GaN films have been deposited by reactive rf sputtering of GaAs target in 100% nitrogen ambient on quartz substrates at different substrate temperatures ranging from room temperature to 700 deg. C. A series of films, from arsenic-rich amorphous to nearly arsenic-free polycrystalline hexagonal GaN, has been obtained. The films have been characterized by phase modulated spectroscopic ellipsometry to obtain the optical parameters, viz., fundamental band gap, refractive index, and extinction coefficient, and to understand their dependence on composition and microstructure. A generalized optical dispersion model has been used to carry out the ellipsometric analysis for amorphous and polycrystalline GaN films and the variation of the optical parameters of the films has been studied as a function of substrate temperature. The refractive index values of polycrystalline films with preferred orientation of crystallites are slightly higher (2.2) compared to those for amorphous and randomly oriented films. The dominantly amorphous GaN film shows a band gap of 3.47 eV, which decreases to 3.37 eV for the strongly c-axis oriented polycrystalline film due to the reduction in amorphous phase content with increase in substrate temperature.},
doi = {10.1063/1.2903443},
url = {https://www.osti.gov/biblio/21137163}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 8,
volume = 103,
place = {United States},
year = {Tue Apr 15 00:00:00 EDT 2008},
month = {Tue Apr 15 00:00:00 EDT 2008}
}