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 co mposition, 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 fab ricated using the optimized conditions. It was found that the trench s urface was extremely rough due to the aluminum micromasking effect. To overcome this effect, a Teflon(TM) sheet was used to cover the cathod e during the experiment. The trenches fabricated using this modificati on 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.