ETCHING PROCESSES FOR FABRICATION OF GAN INGAN/ALN MICRODISK LASER STRUCTURES/

Several new wet and dry etch processes required for fabrication of mic rodisk lasers in the III nitrides have been developed. ICl/Ar electron cyclotron resonance plasmas produce etch rates of 1.3 mu m/ min for G aN 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 investiga ted Cl-2/Ar or CH4/H-2 plasma chemistries. Selectivities of 5-6 over A lN are obtained for these materials. Wet chemical etching of AlN and I nxAl1-xN in KOH-based solutions was found to be a strong function of e tch temperature and material quality. The activation energy for these materials was in the range 2-6 kcal/mol, typical of diffusion-controll ed processes. The KOH solutions did not etch GaN or InN at temperature as high as 80 degrees C. (C) 1996 American Vacuum Society.