Relevance of Threading Dislocations for the Thermal Oxidation of GaN (0001). Issue 1792 (1st June 2015)

• Record Type: Journal Article
• Authors: Reiner, Maria; Koller, Christian; Pekoll, Kurt; Pietschnig, Rudolf; Ostermaier, Clemens
• Editors: Herrick, R.; Miyake, H.; Palacios, T.; Shiojima, K.; Ueda, O.; Chen, Y.; Liliental-Weber, Z.; Narayan, J.; Weber, E.R.
• Is Part Of: MRS proceedings. Issue 1792(2015)
• Publication Date: 2015-06-01
• Subjects: III-V, -- oxidation, -- dislocations; Electrical engineering -- Congresses; Physics -- Congresses; Materials -- Research -- Congresses; Materials science -- Congresses; 620.11
• DOI: 10.1557/opl.2015.557
• Languages: English
• ISSNs: 0272-9172

Abstract

ABSTRACT: The influence of threading dislocations (TDs) on the dry thermal oxidation of c-plane gallium nitride (GaN) is investigated for oxidation temperatures above 800°C. The transformation of GaN to gallium oxide (Ga2 O3 ) is preferably found at TDs and grain boundaries, showing enhanced vertical oxidation, compared to defect free surface sites. Therefore, the increase in surface roughness commonly obtained upon oxidation is explained by an inhomogeneous chemical reactivity associated with those crystal defects. Additionally, annealing in an N2 atmosphere showed that also decomposition is favored at such chemically reactive spots. Comparison between decomposition and oxidation suggests that at temperatures above 950°C, the Ga2 O3 formation is supported by the decomposition of GaN and subsequent oxidation of the metallic gallium.