Fabrication and characterization of a piezoresistive pressure sensor.

Abstract: In this work, we report the fabrication and characterization of a SiC/SiO₂/Si piezoresistive pressure sensor. The sensor structure consists of six PECVD SiC thin-film piezoresistors configured in Wheatstone bridge on a thermally oxidized micromachined silicon diaphragm. In order to fabricate this sensor, three lithographic masks were designed: one to define the square diaphragm (1800 μm×1800 μm), another for the piezoresistors and the third for the Ti/Au metal lines. The diaphragm was formed by anisotropic etching of Si in KOH solution and the piezoresistors by reactive ion etching (RIE) of SiC. The sensor chip size is 4.5 mm×4.5 mm. It was bonded on an alumina substrate using silicone and an aluminum cup was used for protection. The output voltage of the sensor was measured for applied pressure ranging from 0 to 12 psi and voltage suply of 12V. [ABSTRACT FROM AUTHOR]