X‐ray characterization of physical‐vapor‐transport‐grown bulk AlN single crystals

Language
en
Document Type
Article
Issue Date
2020-12-29
First published
2020-08-04
Issue Year
2020
Authors
Wicht, Thomas
Müller, Stephan
Weingärtner, Roland
Epelbaum, Boris
Besendörfer, Sven
Bläß, Ulrich
Weisser, Matthias
Unruh, Tobias
Meissner, Elke
Editor
Publisher
International Union of Crystallography
Abstract

AlN slices from bulk crystals grown under low thermomechanical stress conditions via the physical vapor transport (PVT) method were analyzed by X‐ray methods to study the influence of the growth mode on the crystal quality. Defect types and densities were analyzed along axial [0001] as well as lateral growth directions. X‐ray diffraction (0110) rocking‐curve mappings of representative wafer cuts reveal a low mean FWHM of 13.4 arcsec, indicating the generally high crystal quality. The total dislocation density of 2 × 103 cm−2 as determined by X‐ray topography is low and dislocations are largely threading edge dislocations of b = 1/3⟨1120⟩ type. The absence of basal plane dislocations in homogeneous crystal regions void of macroscopic defects can be linked to the low‐stress growth conditions. Under the investigated growth conditions this high crystal quality can be maintained both along the axial [0001] direction and within lateral growth directions. Exceptions to this are some locally confined, misoriented grains and defect clusters, most of which are directly inherited from the seed or are formed due to the employed seed fixation technique on the outer periphery of the crystals. Seed‐shaping experiments indicate no apparent kinetic limitations for an enhanced lateral expansion rate and the resulting crystal quality, specifically with regard to the growth mode on a‐face facets.

Journal Title
Journal of Applied Crystallography
Volume
53
Issue
4
Citation
Journal of Applied Crystallography 53.4 (2020): S. 1080-1086. <https://scripts.iucr.org/cgi-bin/paper?S1600576720008961>
Zugehörige ORCIDs