STRUCTURAL AND ELECTRICAL CHARACTERIZATION OF PVD-DEPOSITED SNO2 FILMS FOR GAS-SENSOR APPLICATION

Thin SnO2 films for H-2-gas-sensor application have been prepared by r .f. magnetron sputtering. The temperature-dependent electrical conduct ivity is measured in humid synthetic air without and with hydrogen. A model for the electrical conductivity has been developed, which consis ts of two parts, one of them a simple exponential function. We suggest this is caused by a strongly doped interdiffusion layer. An influence of three different glass substrates has been observed. The subtractio n of the interface conductance leads to an H-2 sensitivity that depend s less on the sensor temperature.