Power enhancement of 410-nm InGaN-based light-emitting diodes on selectively etched GaN/sapphire templates

Tsung Yen Tsai*, Dong Sing Wuu, Ming Tsung Hung, Jen Hung Tu, Shih Cheng Huang, Ray-Hua Horng, Wei Yang Chiang, Li Wei Tu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

A selectively etched (SE) GaN template for high-power 410-nm InGaN-based LEDs was fabricated, where 2-μm-thick undoped GaN was grown on recess patterned sapphire substrates (PSSs). This was followed by H3PO 4 selective etching, 0.5-μm-thick SiO2 film deposition, and a final chemical-mechanical polishing process to remove the excess SiO 2. Three kinds of substrates, i.e., conventional sapphire substrates (CSSs), recess PSSs, and SE GaN templates, were used to grow the near-UV LEDs for comparison. The etched pit density of n-type GaN could then be reduced to 105 cm-2, whereas the number of screw-type and edge-type threading dislocations decreased by 16.5% and 49.9%, respectively, since SiO2 fillings on the SE GaN template hindered their propagation. The output power of a near-UV LED fabricated on the SE GaN template was 13% and 46% higher than that of a near-UV LED fabricated on recess PSSs and CSSs, respectively. A substantial improvement in performance can be attributed to the improved epilayer crystallinity and, also, the increased light scattering within the LED induced by SiO2 fillings.

Original languageEnglish
Article number6020776
Pages (from-to)3962-3969
Number of pages8
JournalIEEE Transactions on Electron Devices
Volume58
Issue number11
DOIs
StatePublished - 1 Nov 2011

Keywords

  • 410-nm light emitting diodes (LEDs)
  • InGaN
  • patterned sapphire substrates (PSSs)
  • selectively etched (SE)
  • threading dislocations (TDs)

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