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Removal of Dry-Etch-Induced Surface Layer Damage from p-GaN by Photoelectrochemical Etching


A non-thermal method for removal of surface damage created by dry etching has previously been documented or n-GaN, but no such effort has been reported for p-GaN. In this study, Ga-polar p-GaN films were subjected to inductively coupled plasma reactive ion etching, creating damage near the surface and causing an inversion of the carrier type and concentration from + 5.5 × 1012 cm−2 to − 8.8 × 1010 cm−2, as measured by Hall effect. An application of the carrier-type-selective photoelectrochemical (PEC) etching technique using a KOH and K2S2O8 etch chemistry is employed in order to remove etch-face damage and recover the underlying p-GaN. We show the type selectivity of the PEC etching technique, demonstrating electroless etching of n-GaN while no interaction of the same etch chemistry with p-GaN is observed. Further, surface analysis shows that the PEC etch removes a surface layer from dry-etched p-GaN and increases its roughness substantially, from 0.64 nm to 71 nm RMS.

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The work presented here was funded by a grant from the Advanced Research Projects Agency – Energy (ARPA-E), U.S. Department of Energy under the PNDIODES program directed by Dr. Isik Kizilyalli (Grant No. DE-FOA-00001691).

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Correspondence to V. Meyers.

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Meyers, V., Rocco, E., Hogan, K. et al. Removal of Dry-Etch-Induced Surface Layer Damage from p-GaN by Photoelectrochemical Etching. Journal of Elec Materi (2020).

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  • Gallium nitride
  • dry etching
  • photoelectrochemical etching