University of Essex Nanofab
These pages provide an overview of the semiconductor device research and teaching nanofabrication facilities
Materials Research Society Proceedings 468, 349 (1997)
'...While conventional dry etching techniques have been successfuly applied towards etching of the group-III nitrides, very few wet etchants have identified, a consequence of the unusual chemical inertness of the nitrides. Room temperature etching of AlN has been reported using AZ200K developer, while InN films may be etched in aqueous KOH and NaOH at elevated temperatures. GaN has been found to etch only very slowly (2nm / min) in NH4OH solutions. Since dry etching processes possess a number of significant drawbacks compared to wet etching techniques (such as the formation of ion-induced damage, difficulty in etching layers selectively, and relative complexity), it is important to explore alternative patterning methods. Photochemical (PEC) etching of GaN has recently been demonstrated by Minsky et al. using KOH solution and HeCd laser illumination (325nm). Wet PEC etching has been explored for a variety of semiconductor materials and shown to produce high etch rates, good anisotriopy, as well as high selectivity between materials of different doping and bandgap. In this work we report on the use of broad-area Hg lamp illumination to achieve PEC etching of GaN and AlGaN materials...'
GaN and Related Alloys
Materials Research Society
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