Anodic oxidation of InP in KOH electrolytes
O'Dwyer, Colm; Melly, T.; Harvey, E.; Buckley, D. Noel; Cunnane, V. J.; Sutton, David; Serantoni, M.; Newcomb, Simon B.
Date:
2002-10
Copyright:
© 2002, Electrochemical Society
Citation:
O’Dwyer, C., Melly, T., Harvey, E., Buckley, D. N., Cunnane, V. J., Sutton, D., Serantoni, M. and Newcomb, S. B. (2002) 'Anodic Oxidation of InP in KOH Electrolytes', State-of-the-Art Program on Compound Semiconductors XXXVII (SOTAPOCS XXXVII) / Narrow Bandgap Optoelectronic Materials and Devices, 202nd ECS Meeting, Salt Lake City, Utah, 20-24 October, in Proceedings - Electrochemical Society, Vol. 14, pp. 233-240. ISBN 1-56677-306-5.
Abstract:
The anodic behavior of InP in 1 mol dm-3 KOH was investigated and compared with its behavior at higher concentrations of KOH. At concentrations of 2 mol dm-3 KOH or greater, selective etching of InP occurs leading to thick porous InP layers near the surface of the sustrate. In contrast, in 1 mol dm-3 KOH, no such porous layers are formed but a thin surface film is formed at potentials in the range 0.6 V to 1.3 V. The thickness of this film was determined by spectroscopic ellipsometry as a function of the upper potential and the measured film thickness corresponds to the charge passed up to a potential of 1.0 V. Anodization to potentials above 1.5 V in 1 mol dm- 3 KOH results in the growth of thick, porous oxide films (~ 1.2 µm). These films are observed to crack, ex-situ, due to shrinkage after drying in ambient air. Comparisons between the charge density and film thickness measurements indicate a porosity of approximately 77% for such films.
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