Photoelectrochemical investigation of the etching of gan in H 3PO4

C. Heffernan, D. N. Buckley, C. O'Raifeartaigh

Research output: Contribution to conferencePaperpeer-review

Abstract

The photoelectrochemical (PEC) etching of GaN in H3PO 4 has been studied both as a function of electrolyte pH and illumination intensity. Etching of GaN was found to occur in aqueous H 3PO4 solutions ranging in concentration from 1.0×10-3 mol dm-3 to 5.0 mol dm-3. A peak etch rate of 3.6 nm s-1 was observed at a pH of 0.6. The reduced etch rate at lower pH is attributed to mass transport effects in the higher viscosity H3PO4 electrolyte and at higher pH it is attributed to the formation of a passivating oxide film. The illumination intensity dependence of the PEC etch rate was also investigated in the intensity range 5 mW cm-2 to 50 mW cm-2. Etch rates increased in a roughly linear manner with increasing light intensity. However, they saturated at light intensities greater than ∼34 mW cm-2 indicating a diffusion-limited etching regime. SEM analysis of GaN anodized in 0.001 mol dm-3 H3PO4 revealed the presence of a cracked oxide film on the surface.

Original languageEnglish
Pages552-563
Number of pages12
Publication statusPublished - 2004
EventState-of-the-Art Program on Compound Semiconductors XLI and Nitride and Wide Bandgap Semiconductors for Sensors, Photonics, and Electronics V - Proceedings of the International Symposia - Honolulu, HI, United States
Duration: 3 Oct 20048 Oct 2004

Conference

ConferenceState-of-the-Art Program on Compound Semiconductors XLI and Nitride and Wide Bandgap Semiconductors for Sensors, Photonics, and Electronics V - Proceedings of the International Symposia
Country/TerritoryUnited States
CityHonolulu, HI
Period3/10/048/10/04

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