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Title: Synchrotron radiation x-ray topography and defect selective etching analysis of threading dislocations in GaN

The crystal quality of bulk GaN crystals is continuously improving due to advances in GaN growth techniques. Defect characterization of the GaN substrates by conventional methods is impeded by the very low dislocation density and a large scale defect analysis method is needed. White beam synchrotron radiation x-ray topography (SR-XRT) is a rapid and non-destructive technique for dislocation analysis on a large scale. In this study, the defect structure of an ammonothermal c-plane GaN substrate was recorded using SR-XRT and the image contrast caused by the dislocation induced microstrain was simulated. The simulations and experimental observations agree excellently and the SR-XRT image contrasts of mixed and screw dislocations were determined. Apart from a few exceptions, defect selective etching measurements were shown to correspond one to one with the SR-XRT results.
Authors:
; ; ; ;  [1] ;  [2] ; ;  [3] ;  [4]
  1. Department of Micro- and Nanosciences, Aalto University School of Electrical Engineering, 02150 Espoo (Finland)
  2. Epitaxy Department, Institute of Electronic Materials Technology, 01-919 Warsaw (Poland)
  3. Fraunhofer Institute for Integrated Systems and Device Technology, 91058 Erlangen (Germany)
  4. Kristallographie Institut für Geo- und Umweltnaturwissenschaften, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg (Germany)
Publication Date:
OSTI Identifier:
22314326
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CRYSTALS; DENSITY; ETCHING; GALLIUM NITRIDES; SCREW DISLOCATIONS; SIMULATION; SUBSTRATES; SYNCHROTRON RADIATION; TOPOGRAPHY; X RADIATION