Effects of Electrode Spacing on Reactive Ion Etching of 4H-SiC

Abstract

ABSTRACT4H-SiC was selectively etched in a Reactive Ion Etch (RIE) system using a nickel mask. The power, pressure, and electrode spacing were varied within a RF generated SF6:O2 (1:2) plasma. Peak etch rates of up to 2600 Aring;/min. were obtained at a pressure of 350 mT, power of 90 W (2 W/cm2), and electrode spacing of 3.180 cm. Etches were all residue-free, although power levels above 60 W (1.36 W/cm2) resulted in the SiC surface being roughened, which limited smooth surface etch capability to 2000 Aring;/min. When comparing electrode spacing from 3.180 cm to 1.270 cm, the 3.180 cm spacing was found to have the highest etch rate at pressures ranging from 250 mT to 500 mT.