A 4H-SiC pressure sensor with piezoresistive transducers, for harsh environment applications, e.g., high temperature (~650°C) and/or in corrosive chemicals is presented. The sensing membrane, 1 mm in diameter and 50 µm in thickness, was formed by milling (drilling) a bulk single crystal SiC wafer. Both transverse and longitudinal piezoresistors were formed on the membrane out of an n-type SiC epitaxial layer. Ohmic contacts were obtained with Ta/Ni/Pt metallization followed by annealing at 1000°C for 20 min. The sensor was assembled on a small board and characterized under hydrostatic pressures up to 60 bar at room temperature. The obtained pressure sensitivity was 268 µV/V/bar. The sensor chip was exposed in air at 600°C for 165 hours and changes in bridge resistance were measured.
Philip Johannes Walter Moll, Matthias Carsten Putzke, Yi-Chiang Sun, Chunyu Guo, Jonas De Jesus Diaz Gomez, Maarten Ruud van Delft, Jacopo Oswald
Elison de Nazareth Matioli, Remco Franciscus Peter van Erp, Halil Kerim Yildirim, Jun Ma, Luca Nela, Catherine Erine