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Observation of dislocation etch pits in epitaxial lateral overgrowth GaN by wet chemical etching

Published online by Cambridge University Press:  17 March 2011

T. C Wen
Affiliation:
Department of Electrophysics, And Microelectronics and Information Systems Research Center, National Chiao Tung University, HsinChu, Taiwan, Republic of China
S.C. Lee
Affiliation:
Department of Electrophysics, And Microelectronics and Information Systems Research Center, National Chiao Tung University, HsinChu, Taiwan, Republic of China
H. S. Chuang
Affiliation:
Department of Electrophysics, And Microelectronics and Information Systems Research Center, National Chiao Tung University, HsinChu, Taiwan, Republic of China
C. H. Chiou
Affiliation:
Department of Electrophysics, And Microelectronics and Information Systems Research Center, National Chiao Tung University, HsinChu, Taiwan, Republic of China
W. I Lee
Affiliation:
Department of Electrophysics, And Microelectronics and Information Systems Research Center, National Chiao Tung University, HsinChu, Taiwan, Republic of China
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Abstract

This work investigates dislocation etch pits in epitaxial lateral overgrowth (ELO) GaN by wet chemical etching. A mixture of H2SO4 and H3PO4 was used as a dislocation etchant, and SEM and AFM were employed to observe the surface topography. For the as-grown sample, SEM images present the flat, smooth surface without any pits or hillocks. After the chemical etching, hexagonal shaped etch pits were observed at the edge of ELO GaN. AFM observation of etched ELO GaN displayed high densities of etch pits clustered in the “window” region and the coalescent line of two growing fronts. In contrast, the overgrowth region was nearly free of etch pits. Moreover, we observed that different sizes of etch pits dominated in “window” region and coalescent region. This implied different types dislocations dominated in these regions.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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References

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