Reactive ion etching of trenches in 6H-SiC

In this paper, we report the reactive ion etching (RIE) of trenches in GH-silicon carbide using SF/O-6(2). The plasma parameters: etchant composition, gas-flow rate, chamber pressure, and radio frequency power were optimized to obtain a maximum etch rate of 360 Angstrom min. The etch rate of SiC was found to exhibit a direct correlation with the dc selfbias except when the O-2 percentage was varied. Trenches were fabricated using the optimized conditions. It was found that the trench surface was extremely rough due to the aluminum micromasking effect. To overcome this effect, a Teflon(TM) sheet was used to cover the cathode during the experiment. The trenches fabricated using this modification were found to have smooth etched surfaces and sidewalls. The angle of anisotropy of these trenches was approximately 80 degrees which is suitable for device applications.