HIGHLY SENSITIVE MOSFET GAS SENSORS WITH POROUS PT-SNOX GATE ELECTRODE FOR CO GAS-SENSING APPLICATIONS

Novel gas sensing devices based on a porous Pt-SnOx metal-oxide-semico nductor field-effect transistor (MOSFET) for carbon monoxide (CO) gas sensing have been fabricated for the first time. The structure integra tes the catalytic properties of porous Pt as the thin catalyst layer a nd the gas sensing properties of SnOx as the gas adsorptive oxide with surface-sensitive MOSFETs. The threshold voltage decreased rapidly wi th time when the device was exposed to CO gas. It was possible to dete ct 54 ppm of CO gas with a response time of < 1 min at a device operat ing temperature of 27 degrees C. A model is proposed to explain the op eration. The device detection mechanism of this device presented here corresponds well with the experimental data.