Inductively coupled plasma etching of nano-patterned sapphire for flip-chip GaN light emitting diode applications

Byung Jae Kim, Michael A. Mastro, Hyunjung Jung, Hong Yeol Kim, Sung Hyun Kim, Ron T. Holm, Jennifer Hite, Charles R. Eddy, Joona Bang, Jihyun Kim

Research output: Contribution to journalLetterpeer-review

23 Citations (Scopus)


The flip-chip configuration is employed for the production of high-brightness GaN-based light emitting diodes to improve the extraction of heat. A lithographic approach based on a sacrificial SiO2 nanosphere etch mask was developed to enhance the external extraction of light from the sapphire substrate. Closed-packed arrays of SiO2 nanospheres were prepared by a simple solution-based method on the sapphire substrate. Subsequent dry-etching via inductively coupled plasma using a gas mixture of BCl3 and Cl2 transferred a pattern into the sapphire substrate with the lowest etching at the center of the SiO2 nanosphere. This process created an array of circular cones in the surface of the sapphire that were found to be effective in enhancing the light extraction efficiency through multi-photon scatterings. Room temperature photoluminescence exhibited an increase of 22.5% in intensity after the surface of sapphire was textured.

Original languageEnglish
Pages (from-to)7744-7747
Number of pages4
JournalThin Solid Films
Issue number21
Publication statusPublished - 2008 Sept 1


  • GaN
  • Light emitting diodes
  • Plasma etching
  • Sapphire
  • Surface texturing

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry


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