Surface modification on wet-etched patterned sapphire substrates using plasma treatments for improved GaN crystal quality and LED performance

Kun Ching Shen*, Dong Sing Wuu, Chun Cheng Shen, Sin Liang Ou, Ray-Hua Horng

*Corresponding author for this work

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

A surface-modified wet-etched pyramidal patterned sapphire substrate (PSS) was used to fabricate blue-light InGaN-based light-emitting diodes (LEDs). The pyramidal PSSs were modified using CF4 plasma with different treatment times. It was found that the plasma treatment created a slightly roughened surface pattern, which not only suppressed lateral growth from the incline of the pattern, but also enhanced vertical growth from mesa and groove of the pattern. A clear reduction of GaN dislocation density in PSS LEDs was confirmed by electron microscopy, X-ray diffraction and etch-pit-density measurements. Additionally, the output power of plasma-treated PSS LEDs was 25 higher than that of untreated PSS LED for a 20 mA injection current. The enhanced output power was attributed to the reduction in dislocation density of the GaN film and the enhancement of light scattering by surface-modified PSSs.

Original languageEnglish
JournalJournal of the Electrochemical Society
Volume158
Issue number10
DOIs
StatePublished - 31 Aug 2011

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