title: Identifying threading dislocations in GaN films and substrates by electron channelling.
abstract: Electron channelling contrast imaging of threading dislocations in GaN (0002) substrates and epitaxial films has been demonstrated using a conventional polepiece-mounted backscatter detector in a commercial scanning electron microscope. The influence of accelerating voltage and diffraction vector on contrast features denoting specific threading dislocation types has been studied. As confirmed by coordinated transmission electron microscopy analysis, electron channelling contrast imaging contrast features for edge-type threading dislocations are spatially smaller than mixed-type threading dislocations in GaN. This ability to delineate GaN edge threading dislocations from mixed type was also confirmed by defect-selective etch processing using molten MgO/KOH. This study validates electron channelling contrast imaging as a nondestructive and widely accessible method for spatially mapping and identifying dislocations in GaN with wider applicability for other single-crystal materials.
authors: Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA. rkamalad@andrew.cmu.edu
authors: Ranga J
authors: RJ
authors: Kamaladasa
authors: Fang
authors: F
authors: Liu
authors: Lisa M
authors: LM
authors: Porter
authors: Robert F
authors: RF
authors: Davis
authors: Daniel D
authors: DD
authors: Koleske
authors: Greg
authors: G
authors: Mulholland
authors: Kenneth A
authors: KA
authors: Jones
authors: Yoosuf N
authors: YN
authors: Picard