ETCHING OF 6H-SIC AND 4H-SIC USING NF3 IN A REACTIVE ION ETCHING SYSTEM

The use of pure NF3 source gas in reactive ion etching of bulk and epi taxy, Si-face, 6H-SiC, and 4H-SiC is reported. The effects of RF power and chamber pressure on etch rate and surface morphology are discusse d. A process developed for a smooth, residue-free etch, with a relativ ely high etch rate of similar to 1500 Angstrom/min is examined using s canning electron microscopy and Auger electron spectroscopy surface an alysis. The process developed had a self-induced de bias ranging from 25 to 50 V, a forward RF power of 275 W (1.7 W/cm(2)), chamber pressur e of 225 mT, and a NF3 now rate between 95 and 110 seem. No chemical r esidue or aluminum micromasking was observed on any of the samples etc hed with the above process.