Silicon-carbide Schottky diodes with sputtered and laser-ablated thin-Pt gate as NO gas sensors in high temperature

Abstract

We fabricated thin catalytic metal gate Schottky diodes prepared with Pt gates deposited by sputter and laser ablation method on SiC substrates responding to NO gas at high temperature. Schottky barrier height, ideality factor and series resistance were evaluated from linear G/I/spl times/G plots. Upon exposure to NO gas, the barrier height decreased, ideality factor increased and series resistance decreased and as a whole effect, forward current of the devices was increased. Change of barrier height was larger for 4H-SiC Schottky diodes than 6H-SiC Schottky diodes. The devices were tested for NO gas concentrations from 5 ppm to 50 ppm and showed reversible and stable response at temperatures up to 450/spl deg/C.