This work focusses on the design and fabrication of surface micromachined pressure sensors, designed in a modular way for the integration with analog front-end read-out electronics. Polycrystalline 3C silicon carbide (SiC) was used to fabricate free-standing high topography cavities exploiting surface micromaching. The poly-SiC was in-situ doped and the membrane itself is used as piezoresistive element, thereby forming a so-called self-sensing membrane, favoring ease of fabrication. After sacrificial release, the cavity is sealed by conformal deposition of poly-SiC whereby the reference pressure of the absolute pressure sensor is determined by the pressure during sealing in the fabrication step. Aluminum and titanium metallizations were used and ohmic contacts were confirmed by waferscale measurements. Measurements were carried out on different devices ranging from 100 kPa down to 10 Pa at room temperature. The Wheatstone bridge yields a logarithmic response of 1.1mVbar-1 V-1. A square 300 μm device exhibits a logarithmic impedance behavior yielding a response of ΔR/R of 1.6 × 10-3 bar-1. The realized pressure devices are a first step toward a SiC ASIC + MEMS platform for intended operation in harsh environments, such as industrial process monitoring, combustion control or structural health monitoring. The future outlook of the integration concept implies extended functionality by front-end transducer read-out, signal amplification and communication.
Original languageEnglish
Number of pages10
JournalIEEE Sensors Journal
Publication statusAccepted/In press - 2020

    Research areas

  • Silicon Carbide, Absolute Pressure Sensor, MEMS, Surface Micromaching

ID: 73865671