From Memory to Sensor: Ultralow Power and High Selectivity Hydrogen Sensor Based on ReRAM Technology

A novel hydrogen sensor has been developed by using an optimized 0.18-μm resistive random access memory process with a Pt/Ta
₂
O
₅
/TaO
_x
/TaN stack. This resistive hydrogen sensor (ReHsensor) conforms to the ISO26142 standard in which it exhibits exceptional sensing capabilities, including a short response time (about 20 s for 1 vol.% hydrogen gas), high sensitivity, wide hydrogen concentration detection range (up to 4 vol.%) in air and N
₂
ambient, high gas selectivity (no reaction with CH
₄
, CO, CH
₃
OH, or CH
₃
COCH
₃
) and is immune to poisoning by SO
₂
and hexamethyl disiloxane. As it does not require a heater, the power consumption of the ReHsensor is very low, at 0.4 mW.