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

H. Y. Lin, Y. J. Chen, C. L. Chang, X. F. Li, Cheng-Huang Kuo, S. C. Hsu, C. Y. Liu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Chemical wet etching on c-plane sapphire wafers by three etching solutions (H 3PO 4, H 2SO 4, and H 3PO 4/H 2SO 4 mixing solution) was studied. Among these etching agents, the mixing H 3PO 4/H 2SO 4 solution has the fastest etching rate (1.5 μm/min). Interestingly, we found that H 2SO 4 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%.

Original languageEnglish
Pages (from-to)971-977
Number of pages7
JournalJournal of Materials Research
Volume27
Issue number6
DOIs
StatePublished - 28 Mar 2012

Keywords

  • III-V
  • Semiconducting

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