New thin-film humidity and thermal micro-sensor with Al/SrNbxTi1-xO3/SiO2/Si structure

Abstract

Strontium titanate-niobate (SrNbxTi1-xO3) film deposited on a SiO2/Si substrate by the argon ion-beam sputtering technique is used to fabricate thin-film resistors and metal-insulator-semiconductor (MIS) capacitors by standard integrated-circuit technology. Results show that the film resistor has superior thermal-sensitivity characteristics within the temperature range of 27-200 °C, and the MIS capacitor is highly sensitive to relative humidity. Besides investigating the effects of frequency on the impedance of the film resistor at various temperatures and on the current of the MIS capacitor at low and high relative humidities, the response times of the MIS capacitor to adsorption and desorption of water vapor are found to be reasonably short (15 s and 10 s) and its humidity hysteresis can be greatly suppressed at higher operating voltages.