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Characterization study of GaN-based epitaxial layer and light-emitting diode on nature-patterned sapphire substrate

Published online by Cambridge University Press:  06 February 2012

H.Y. Lin ,
Y.J. Chen ,
C.L. Chang ,
X.F. Li ,
C.H. Kuo ,
S.C. Hsu  and
C.Y. Liu
H.Y. Lin
Affiliation:
Department of Chemical and Materials Engineering, National Central University, Jhongli City, Taiwan 32001, Republic of China
Y.J. Chen
Affiliation:
Department of Chemical and Materials Engineering, National Central University, Jhongli City, Taiwan 32001, Republic of China
C.L. Chang
Affiliation:
Department of Chemical and Materials Engineering, National Central University, Jhongli City, Taiwan 32001, Republic of China
X.F. Li
Affiliation:
Department of Chemical and Materials Engineering, National Central University, Jhongli City, Taiwan 32001, Republic of China
C.H. Kuo
Affiliation:
Institute of Lighting and Energy Photonics, National Chiao Tung University, Tainan City, Taiwan 30010, Republic of China
S.C. Hsu
Affiliation:
Department of Chemical and Materials Engineering, Tamkang University, New Taipei City, Taiwan 25137, Republic of China
C.Y. Liu*
Affiliation:
Department of Chemical and Materials Engineering, National Central University, Jhongli City, Taiwan 32001, Republic of China
*
a)Address all correspondence to this author. e-mail: chengyi@cc.ncu.edu.tw
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Abstract

Chemical wet etching on c-plane sapphire wafers by three etching solutions (H3PO4, H2SO4, and H3PO4/H2SO4 mixing solution) was studied. Among these etching agents, the mixing H3PO4/H2SO4 solution has the fastest etching rate (1.5 μm/min). Interestingly, we found that H2SO4 does not etch the c-plane sapphire wafer in thickness; instead, a facet pyramidal pattern is formed on the c-plane sapphire wafer. GaN light-emitting diode (LED) epitaxial structure was grown on the sapphire wafer with the pyramidal pattern and the standard flat sapphire wafer. X-ray diffraction and photoluminescence measurement show that the pyramidal pattern on the sapphire wafer improved crystalline quality but augmented the compressive stress level in the GaN LED epilayer. The horizontal LED chips fabricated on the pyramidal-patterned sapphire wafer have a larger light output than the horizontal LED chips fabricated on the standard flat sapphire wafer by 20%.

Keywords

III–VSemiconducting
Type
Articles
Information
Journal of Materials Research , Volume 27 , Issue 6 , 28 March 2012 , pp. 971 - 977
Copyright
Copyright © Materials Research Society 2012

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