Plasma-deposited amorphous silicon carbide films for micromachined fluidicchannels

The stress properties of the a-SiC:H films on Si by plasma-enhanced chemica l 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 th ermal cycles was found in the carbon-rich samples. Moreover, a new method t o fabricate microchannels by through-hole etching with subsequent planariza tion is proposed. The process is based on etching out the deep grooves thro ugh a perforated a-SiC:PI 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 etc h is performed at low temperatures (< 50 degrees C), The process technology is demonstrated on the fabrication of microfluidic channels with the low-s tress (<0.1 GPa) a-SiC:H membranes. (C) 1999 Elsevier Science B.V. All righ ts reserved.