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 language | English |
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Pages | 552-563 |
Number of pages | 12 |
Publication status | Published - 2004 |
Event | State-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 2004 → 8 Oct 2004 |
Conference
Conference | State-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 |
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Country/Territory | United States |
City | Honolulu, HI |
Period | 3/10/04 → 8/10/04 |