Zero offset drift suppression in SiC pressure sensors at 600 °C

Temporal drifts in zero pressure offset voltage, V
_oz
, observed in piezoresistive silicon carbide (SiC) pressure sensors at 600 °C were significantly suppressed to allow reliable operation. By modifying the bondpad/contact metallization, the Vη relative drift velocity at 600 °C was suppressed to within ± 0.5 mV.hr
^-1
, for over 1000 hours. Microstructural changes within the contact metallization were analyzed with Auger Electron Spectroscopy (AES) and Scanning Electron Microscopy (SEM). This metallization scheme may improve SiC pressure sensor reliability in short duration ground/flight tests and lower temperature (~300 °C) remote pressure monitoring (i.e., geothermal, and deep well drilling).