MEMS structures using polycrystalline diamond single-material micro technologies

Large band gap materials such as diamond (5.5 eV) and AlN (6 eV) offer the possibility of making MEMS structures out of a single material by varying the doping level to achieve the semi-conducting, metallic and insulating (undoped) properties needed in a typical MEMS structure. Polycrystalline diamond (poly-C), which has recently been used in the fabrication of BioMEMS, RFMEMS, and MEMS packaging, is inexpensive and retains many of the unique properties of single-crystal diamond. However, the development of diamond-based SMM technology faces a number of challenges including (a) producing highly-insulating and highly-conducting poly-C films, (b) creating ohmic contacts, and (c) patterning by dry etching of poly-C films grown on SiO₂. The results presented in this paper, which addresses these issues for the first time, are expected to lead to SMM based MEMS structures and packaging.