PECVD silicon carbide for micromachined transducers

We report preliminary work on PECVD amorphous hydrogenated silicon carbide (a-SiC:H) as a material with many potential applications in micromachined transducers. Four examples are presented: an electrochemical probe; a fully packaged, encapsulated pressure sensor; a sealed and coated microfluidic channel; and deep etched channels in glass. A designed experiment was undertaken in an attempt to correlate stress, resistivity and wet etchability with the following process parameters: pressure, CH₄ flow rate, low frequency power, low frequency cycle time, high frequency power, and high frequency cycle time. While this preliminary work does demonstrate a CMOS compatible, insulating thin film with low stress (<100 MPa compressive), high etch resistance, and conformal coating, the complexity of the plasma chemistry will require further investigation to elaborate parameter dependencies