Defect-selective etching was developed for scandium, nitride (ScN) crystals. ScN crystals were etched in fused KOH/NaOH eutectic mixtures between 180 and 440 degrees C for up to 10min. Several etch pit shapes were observed, and their formation was dependent on the etching temperature. The different etch pit shapes probably originated from different crystalline orientations and defect types. Square etch pits with steps formed at screw and mixed dislocations, as verified by transmission electron microscopy. The density of the etch pits was on the order of 10(4)-10(6) cm(-2) for bulk ScN crystals produced by sublimation. (c) 2006 Elsevier B.V. All rights reserved.