High resolution x-ray diffraction analysis of GaN-based heterostructures grown by OMVPE

Book · Wed Dec 31 04:00:00 EST 1997

OSTI ID:581088

Goorsky, M S ^[1]; Polyakov, A Y; Skowronski, M; Shin, M; Greve, D W ^[2]

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1. Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering
2. Carnegie Mellon Univ., Pittsburgh, PA (United States)

The authors demonstrate the use of triple axis diffraction measurements, including {Phi} scans (in which the sample is rotated about an axis perpendicular to its surface) to assess the crystal perfection of wurtzite GaN layers on sapphire grown using different pre-nitridation growth treatments by organometallic vapor phase epitaxy. The {Phi} scans determine the in-plane misorientation angles between the crystallites and hence provide information on the edge dislocation density. Using glancing incidence (1014) and (1015) reflections, they determined that the misorientation among the GaN crystallites decreases with increasing layer thickness and that the pre-nitridation conditions control the initial level of misorientation. Triple axis {omega} and {omega}-2{theta} scans around the (0002) reflection did not show a systematic trend with increasing layer thickness. However, layers grown without a pre-nitridation step tended to exhibit higher values of both mosaic spread and strain. The appropriate asymmetric reflections for GaN-based {Phi} scan measurements are determined using structure factor calculations, which are presented here.

• OSTI ID: 581088
• Report Number(s): CONF-961202--; ISBN 1-55899-353-3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL DEFECTS
EXPERIMENTAL DATA
GALLIUM NITRIDES
HETEROJUNCTIONS
MICROSTRUCTURE
STRUCTURE FACTORS
X-RAY DIFFRACTION