Several new wet and dry etch processes required for fabrication of microdisk lasers in the III nitrides have been developed. ICl/Ar electron cyclotron resonance plasmas produce etch rates of 1.3 mu m/ min for GaN and 1.15 mu m/min for InN at 1000 W microwave power and 250 W Of rf power. These rates are substantially faster than previously investigated Cl-2/Ar or CH4/H-2 plasma chemistries. Selectivities of 5-6 over AlN are obtained for these materials. Wet chemical etching of AlN and InxAl1-xN in KOH-based solutions was found to be a strong function of etch temperature and material quality. The activation energy for these materials was in the range 2-6 kcal/mol, typical of diffusion-controlled processes. The KOH solutions did not etch GaN or InN at temperature as high as 80 degrees C.