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Direct observation of stress relaxation process in 4H-SiC homoepitaxial layers via in situ synchrotron x-ray topography

DOI: 10.4028/ DOI Help

Authors: Jian Qiu Guo (Stony Brook University) , Yu Yang (Stony Brook University) , Balaji Raghothamachar (Stony Brook University) , Michael Dudley (Stony Brook University) , Swetlana Weit (Universit├Ąt Freiburg) , Andreas N. Danilewsky (Universit├Ąt Freiburg) , Patrick J. Mcnally (Dublin City University) , Brian K. Tanner (Durham University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Materials Science Forum , VOL 924 , PAGES 176 - 179

State: Published (Approved)
Published: June 2018
Diamond Proposal Number(s): 13464

Abstract: During 4H silicon carbide (4H-SiC) homoepitaxy and post-growth processes, the development of stress relaxation has been observed, in which interfacial dislocations (IDs) are formed at the epilayer/substrate interface, relaxing the misfit strain induced by the nitrogen doping concentration difference between the epilayer and substrate. It is widely believed that an interfacial dislocation is created by the glide of a mobile segment of a basal plane dislocation (BPD) in the substrate or epilayer towards the interface, leaving a trailing edge component right at the interface. However, direct observation of such mechanisms has not been made in SiC before. In this work, we present an in situ study of the stress relaxation process, in which a specimen cut from a commercial 4H-SiC homoepitaxial wafer undergoes the stress relaxation process during a high-temperature heat treatment while sequential synchrotron white beam X-ray topographs were recorded simultaneously. Based on the dynamic observation of this process, it can be concluded that thermal stress plays a role in the relaxation process while the increased misfit strain at elevated temperature most likely drives the formation of an interfacial dislocation.

Journal Keywords: SiC; relaxation; epitaxy

Subject Areas: Materials, Physics, Technique Development

Instruments: B16-Test Beamline

Added On: 31/10/2018 10:07

Discipline Tags:

Materials Engineering & Processes Physics Materials Science Engineering & Technology

Technical Tags:

Microscopy X-ray Microscopy Topography