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Preparation of 30×30 mm2 Free-Standing GaN Wafer by Mechanical Liftoff and Optical Properties in The Backside of The Free GaN by Cathodoluminescence

Published online by Cambridge University Press:  17 March 2011

Hwa-Mok Kim
Affiliation:
Quantum-functional Semiconductor Research Center, Dongguk University, Seoul 100-715, Korea
Jae-Eung Oh
Affiliation:
EM&C, School of Electrical and Computer Engineering, Hanyang University, Ansan 425-791, Korea
Tae-Won Kang
Affiliation:
Quantum-functional Semiconductor Research Center, Dongguk University, Seoul 100-715, Korea
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Abstract

In this study, free-standing GaN was produced from 350- to 400-μm-thick GaN films grown on sapphire by using hydride vapor phase epitaxy. The thick films were separated from the substrate by using the mechanical polishing method with a diamond slurry. After liftoff, the bow is slight or absent in the resulting free-standing GaN. Double-crystal X-ray diffraction, hall measurements, and cathodoluminescence were used for characterizing the free-standing GaN wafer. To investigate spatially the backside of the free-standing GaN substrate, we controlled the electron beam energy from 5 keV to 30 keV. As the beam energy increased, dark regions, i.e., nonradiative regions, become smaller than bright regions. We think this means that nonradiative centers, i.e., threading dislocations, merge during film growth.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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References

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