Effects of type of reactor, crystallinity of SiC, and NF3 gas pressure on etching rate and smoothness of SiC surface using NF3 gas plasma

Polycrystalline beta-SiC and single-crystalline 4H-SiC surfaces were etched by reactive ion etching (RIE) using NF3 gas plasma. A smooth surface was obtained on the polycrystalline SiC after RIE at NF3 gas pressures of 2 and 10 Pa for 10 min, and neither spikes nor pillars were formed on it. On the other hand, some pillars were formed on the single-crystalline SiC surface by RIE at NF3 gas pressures of 2 and 10 Pa. Though the absence of carbon-rich regions and SiOx on the outermost surface before etching was confirmed by x-ray photoelectron spectroscopy and Raman analysis, x-ray diffraction analysis revealed that graphite crystallites were present in the single-crystalline SiC bulk. It was concluded that the graphite crystallites acted as masks and the pillars grew up from the graphite crystallites in the single crystalline SiC during RIE. (C) 2009 American Vacuum Society. [DOI: 10.1116/1.3222938]