Reaction-limited wet etching of CuCrO2

An (NH4)(2)Ce(NO3)(6)/HNO3/H2O solution was used to obtain wet etch rates at 25 degrees C in the range 500-1000 angstrom min(-1) for CuCrO2 grown on sapphire substrates by pulsed laser deposition. The etching was reaction-limited, with an activation energy of 11.9 kCal mol(-1). Under these conditions, the etching of ZnO grown in a similar fashion was much faster (similar to 5 mu m min(-1)), providing highly selective removal of ZnO from CuCrO2. In addition, the conventional etchants for ZnO (HCl, HNO3, H3PO4) did not etch the CuCrO2. Simple photoresist masking can be used with the (NH4)(2)Ce(NO3)(6)/HNO3/H2O mixtures to allow patterning of device structures. (c) 2007 The Electrochemical Society.