Plasma chemistries for high density plasma etching of SiC

A variety of different plasma chemistries, including SF₆, Cl₂, ICl, and IBr, have been examined for dry etching of 6H-SiC in high ion density plasma tools (inductively coupled plasma and electron cyclotron resonance). Rates up to 4500Å-min^?1 were obtained for SF₆ plasmas, while much lower rates (≤800Å·min^?1) were achieved with Cl₂, ICl, and IBr. The F₂-based chemistries have poor selectivity for SiC over photoresist masks (typically 0.4–0.5), but Ni masks are more robust, and allow etch depths ≥10 µm in the SiC. A micromachining process (sequential etch/deposition steps) designed for Si produces relatively low etch rates (<2,000Å-min^?1) for SiC.