High Temperature Reliability of High-k/SiC MIS Hydrogen Sensors

In this work a Pt/HfO2/SiO2/SiC MIS capacitor is exposed in air at 400°C for 1000 hours, with its oxide capacitance, flatband voltage and density of interface traps being measured at various time intervals. After the structure has been shown to operate reliably for extensive periods of time at 400°C, the C-V characteristics of a device from the same fabrication batch are measured at 300°C in different concentrations of H2 and examined for sensitivity. The results demonstrate that gas sensitive MIS capacitors incorporating high-ĸ dielectrics, have the potential to operate at extreme temperatures for long periods of time. This makes them suitable for deployment in hostile conditions, where regular servicing may not be possible.