Piezoresistive Effect in SiOC Ceramics for Integrated Pressure Sensors
Abstract:Piezoresistivity was found in silicon oxycarbide (SiOC) ceramics synthesized using a polymer-to-ceramic transformation process. A commercial polysiloxane, namely poly(methylsilsesquioxane), was used as the starting material. The SiOC ceramic synthesized at 1400°C exhibits high piezoresistivity, leading to strain sensitivities (k factors) of ∼145, while lower pyrolysis temperatures (1000°–1300°C) do not show a piezoresistive effect. Structural characterization by X-ray diffraction in combination with micro-Raman spectroscopy revealed that with increasing pyrolysis temperature, the content of free carbon in the X-ray amorphous SiOC matrix increases without changes in the overall composition. Percolation effects related to the carbon-based phase segregated from the SiOC matrix are responsible for the piezoresistivity analyzed in the SiOC ceramic.
Document Type: Research Article
Affiliations: 1: Technische Universität Darmstadt, Institut für Materialwissenschaft, 64287 Darmstadt, Germany 2: Technische Universität Darmstadt, Fachbereich Maschinenbau, 64289 Darmstadt, Germany 3: Fraunhofer Institute for Structural Durability and System Reliability, 64289 Darmstadt, Germany
Publication date: April 1, 2010