Deep and alignment free patterned etching of GaN surface using an atomic force microscope

Jih Shang Hwang*, Der Chang Chen, Li Wei Chen, Zhan Shuo Hu, Zen Yu You, Chih Chiang Wu, Tai Yuan Lin, Tsong Ru Tsai, Surojit Chattopadhyay

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Successful deep and alignment-free patterned etching on GaN using atomic force microscope (AFM) local oxidation followed by in-situ chemical etching is demonstrated. Oxide ridges are grown on GaN on an AFM by applying positive sample bias at 80% humidity, with the oxidation reaction expedited by UV light. The oxide ridges are then etched by HCl solution, leaving troughs in the GaN surface. A dripping strategy for the in-situ chemical etching is recommended that allows deep, alignment-free multiple AFM oxidation/etching works on the GaN surface without any need of substrate removal from the AFM platform. Repeated etching followed by AFM oxidation on a spot on a GaN surface resulting in a hole as deep as 800 nm was also demonstrated. Further, a preliminary evaluation of the porosity of the AFM-grown oxide indicates that the oxide ridges grown on GaN at an AFM cantilever moving speed of 300 nm/s are porous in structure, with an estimated porosity of 86%, which porosity could be reduced if longer resident time of the AFM cantilever on the target oxidation region was used.

Original languageEnglish
Pages (from-to)3979-3984
Number of pages6
JournalJournal of Nanoscience and Nanotechnology
Issue number5
StatePublished - May 2011


  • Atomic-force microscopy
  • GaN
  • Light-emitting diodes
  • Local oxidation
  • Nano-etching


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