Electrical properties of Ba/sub 0.8/Sr/sub 0.2/TiO/sub 3/ thin film with NTC effect [thin film resistor]

Ba/sub 0.8/Sr/sub 0.2/TiO/sub 3/ thin films, deposited on a SiO/sub 2//Si substrate by an argon ion-beam sputtering technique, are used to fabricate thin-film resistors by standard integrated-circuit technology. The resistance-temperature characteristics of the thin-film resistor show that the thin-film resistor has good thermal sensitivity with negative temperature coefficient from room temperature to 200/spl deg/C (-5.3%/spl deg/C/sup -1/ at 30/spl deg/C for a test voltage of 6 V) as opposed to the positive temperature coefficient of the same material in sintered ceramic form. The current-voltage characteristics reveal that in the low-voltage region,. thermionic emission is dominant, while in the high-voltage range, a space-charge limited conduction mechanism plays a major role. In the medium-voltage range, there is the normal ohmic behavior. The effects of frequency on the impedance of the thin-film resistor at various temperatures are also investigated.