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Proceedings Paper

Point defect management in GaN by Fermi-level control during growth
Author(s): Marc P. Hoffmann; James Tweedie; Ronny Kirste; Zachary Bryan; Isaac Bryan; Michael Gerhold; Zlatko Sitar; Ramón Collazo
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Paper Abstract

A point defect control scheme is demonstrated, to control point defects during the growth of doped wide bandgap semiconductors. First the theoretical description of this new concept is presented, second GaN:Mg is used as a model system and as an experimental example to show its feasibility. It can be shown that above bandgap UV-light illumination during the growth can reduce the passivation and compensation of Mg acceptors in GaN:Mg. The amount of hydrogen impurities, that usually passivates Mg at doping concentrations around Mg:2x1019 cm-3, is significantly reduced by UVillumination. The resistivity of samples grown with UV is similar to the resistivity of post-growth annealed samples. No post growth annealing was needed. In contrast samples that are doped below Mg:<1x1018 cm-3 become n-type conductive when the samples are grown with UV illumination. This observation suggests a reduced incorporation of Mg acceptors due to the UV light. At low Mg doping concentrations the native donor incorporation by O donors dominates the conductivity over Mg acceptors. UV-illumination therefore reduces compensation of donors by Mg acceptors. Thus, these observations support the concept of UV illumination as a way to control the Fermi level of different charged point defects to control compensation in doped semiconductors.

Paper Details

Date Published: 8 March 2014
PDF: 7 pages
Proc. SPIE 8986, Gallium Nitride Materials and Devices IX, 89860T (8 March 2014); doi: 10.1117/12.2041018
Show Author Affiliations
Marc P. Hoffmann, North Carolina State Univ. (United States)
James Tweedie, North Carolina State Univ. (United States)
Ronny Kirste, North Carolina State Univ. (United States)
Zachary Bryan, North Carolina State Univ. (United States)
Isaac Bryan, North Carolina State Univ. (United States)
Michael Gerhold, U.S. Army Research Office (United States)
Zlatko Sitar, North Carolina State Univ. (United States)
Ramón Collazo, North Carolina State Univ. (United States)

Published in SPIE Proceedings Vol. 8986:
Gallium Nitride Materials and Devices IX
Jen-Inn Chyi; Yasushi Nanishi; Hadis Morkoç; Joachim Piprek; Euijoon Yoon; Hiroshi Fujioka, Editor(s)

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