Plasma-deposited amorphous silicon carbide films for micromachined fluidic channels

The stress properties of the a-SiC:H films on Si by plasma-enhanced chemical vapor deposition PECVD.are investigated. It is found that the stability of the a-SiC:H films relates to Si–H bonds breaking and changes the stress toward tensile. No evident reduction in the content of Si–H bonds after thermal cycles was found in the carbon-rich samples. Moreover, a new method to fabricate microchannels by through-hole etching with subsequent planarization is proposed. The process is based on etching out the deep grooves through a perforated a-SiC:H membrane, where poly-Si is used as a sacrificial layer to define the channel structure, followed by PECVD sealing the SiC:H membrane. In order to improve the etching performance, the agitated KOH etch is performed at low temperatures -508C.. The process technology is demonstrated on the fabrication of microfluidic channels with the low-stress -0.1 GPa.a-SiC:H membranes. q1999 Elsevier Science B.V. All rights reserved.