title: Effect of annealing on the properties of indium-tin-oxynitride films as ohmic contacts for gan-based optoelectronic devices.
abstract: Indium-tin-oxynitride (ITON) films have been fabricated by rf sputtering from an indium-tin-oxide target in nitrogen plasma. The influence of postdeposition annealing up to 800 degrees C is analyzed by electrical, optical, and surface characterization of the films in comparison to indium-tin-oxide (ITO) films fabricated in argon plasma. High-temperature annealing resulted in ITO(N) films with similar carrier concentrations. However, the resistivity and optical transmittance of the ITON films were higher than those of the ITO films. Photoelectron spectroscopy revealed that nitrogen is incorporated into the ITON structure in an unbound state as well as through the formation of metal-nitrogen and oxynitride bonds that decorate oxygen vacancies. When the core level electron spectra of ITO and ITON films are compared, a correlation between carrier concentration and the incorporated nitrogen is found. Changes in ITON electrical properties are mainly induced by the release of nitrogen at temperatures above 550 degrees C. In this context, ohmic contact behavior was achieved for ITON on p-type GaN after annealing at 600 degrees C, while no ohmic contact could be realized using ITO.
authors.affiliation: Institute of Micro- and Nanotechnologies, TU Ilmenau, P.O. Box 100565, 98684 Ilmenau, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Himmerlich
authors.forename: Maria
authors.initials: M
authors.lastname: Koufaki
authors.forename: Gernot
authors.initials: G
authors.lastname: Ecke
authors.forename: Christof
authors.initials: C
authors.lastname: Mauder
authors.forename: Volker
authors.initials: V
authors.lastname: Cimalla
authors.forename: Juergen A
authors.initials: JA
authors.lastname: Schaefer
authors.forename: Antonis
authors.initials: A
authors.lastname: Kondilis
authors.forename: Nikos T
authors.initials: NT
authors.lastname: Pelekanos
authors.forename: Mircea
authors.initials: M
authors.lastname: Modreanu
authors.forename: Stefan
authors.initials: S
authors.lastname: Krischok
authors.forename: Elias
authors.initials: E
authors.lastname: Aperathitis