Low-damage etching of silicon carbide in Cl₂-based plasmas

Fluorine-based plasmas have been extensively reported for etching SiC in inductively coupled plasma reactive ion etching (ICP-RIE) systems for device fabrication and via-hole formation. The primary advantage of fluorine-based plasmas for etching SiC is that they yield very high etch rates. However, while high etch rates are very suitable for via-hole formation into SiC, lower etch rates are desirable for SiC device fabrication. The etching of SiC using ICP-RIE in various Cl₂-based mixtures is reported. It was found that in comparison with F₂-based gas mixtures, Cl₂-based gas mixtures induced less damage on etched SiC surfaces. Optimized etching conditions using BCl₃/SF₆ gas mixtures that induce minimal surface damage on SiC are reported. Results of Auger electron spectroscopy showed that etching conditions produced negligible change in surface stoichiometry.