Processing and characterization of silicon carbon-nitride ceramics: application of electrical properties towards MEMS thermal actuators

This paper reports the development of electrically conductive silicon carbon-nitride (SiCN) for harsh-environment MEMS applications. SiCN is a new class of polymer-derived bulk ceramics for ultra-high temperature and corrosive environment applications; however, aspyrolyzed SiCN is electrically insulating. Through post-pyrolysis annealing at 1400 degreesC in a hot isostatic press in a nitrogen atmosphere poly(urea-methyl-vinyl)silazane-derived SiCN MEMS devices were fabricated that exhibit a room temperature electrical resistivity of 2-5.5 Ohm cm. The material was examined using linear four-probe, X-ray diffraction, Fourier transform infrared spectroscopy and SEM. This integrated materials/micromachining process enables the realization of a new class of (electro-thermo-mechanical) devices not previously possible in SiCN, and thus takes polymer-derived ceramic (PDC) microsystems technology to the next level of complexity. SiCN lateral thermal actuators and micro-grippers for moving chip-sized objects were fabricated to demonstrate an application of this functionalized material. This work is the first to demonstrate electro-thermo-mechanical transducers fabricated from polymer-derived SiCN. (C) 2003 Elsevier Science B.V. All rights reserved.