Surface micromachining of polycrystalline SiC films using microfabricated molds of SiO2 and polysilicon

As an alternative to conventional SiC reactive ion etching (RIE), polycrystalline (poly-SiC) films were patterned into micron-sized structures using sacrificial SiO2 and polycrystalline silicon (polysilicon) molds in conjunction with mechanical polishing. The molds were made from thermally grown SiO2 and LPCVD polysilicon films and were fabricated using conventional patterning techniques. The poly-SiC micromolding process combines film deposition, polishing, and selective wet chemical etching of the molds to achieve the desired pattern. The process is simple and does not suffer from the difficulties associated with RIE of SiC. Micrometer-sized lines, spaces, and complex device structures have been patterned using this technique. The micromolding technique has been used in a SiC surface micromachining process to fabricate fully released lateral resonant structures.