Dual gate FET hydrogen gas sensor

Abstract

We developed a dual gate FET hydrogen gas sensor for application to hydrogen vehicles. The dual gate FET hydrogen sensor was integrated with Pt-gate FET to detect hydrogen and Ti-gate FET as the reference sensor in the same Si chip. Ti-gate FET has the same structure as Pt-FET except for the gate metal. The Pt-FET showed good response to hydrogen gas above 10 ppm in air, while the Ti-FET did not show any response to hydrogen gas. The differential output voltage between the Pt-FET and the Ti-FET was stable in the range of room temperature to 80˚C because of the same temperature dependence of the I-V characteristic.

Comparison of Hydrogen-Induced Oxide Charges Among GaN Metal-Oxide-Semiconductor Capacitors with Al2O3, HfO2, or Hf0.57Si0.43Ox Gate Dielectrics

“…Meanwhile, a catalytic gate metal has been reported to be critical for observing hydrogen-induced V fb shifts. 34 We speculate that reactive atomic hydrogen is necessary in order to observe the V fb shift. Hydrogen molecules adsorbed onto the catalytic gate metal dissociate into atomic hydrogen and diffuse into the dielectric layers to be positively charged, thereby changing the V fb .…”