Abstract
Detection of flammable and toxic gases is a subject of growing importancein both domestic and industrial environments. Different deviceconfigurations based on metal oxides have been used so far. MIM is onesuch important configuration to achieve high sensitivity and fastresponse.Polycrystalline titanium dioxide was grown by thermal oxidation at 800oCon 0.25 mm thick titanium substrates with gold coating on the backsurface. Resistivity, carrier density & mobility were measured at roomtemperature. The grown oxide showed n-type conducitivity. Pd metal dots(1.5 mm dia) were deposited on the oxide surface, using e-beam evaporationtechnique, to fabricate Pd/TiOx/Ti-Au (x<2) MIM sensor structure. The I-Vstudy was carried out with 500 ppm hydrogen in the temperature range 200 -350oC and the current increased upon exposure to hydrogen. The sensitivityand the change in barrier height were calculated and were found tomaximize at 300oC beyond which the values started decreasing. The responsetime as calculated from the transient response characteristics was 16 secat 300oC.In this talk, the thin film preparation technique and associatedcharacterizations along with the sensor response will be discussed indetail.
