Stability of thick film piezoresistors under large pressure cycles at elevated temperature

The resistance change of ruthenium based metal-insulator-metal (MIM) thick film resistors with hydrostatic pressure exhibits excellent linearity, no hysteresis, a small temperature dependency, and an order of magnitude greater sensitivity than the longitudinal mode. The effect of long-term 10/sup 6/ hydrostatic pressure cycles (0 to /spl sim/21 MPa) at 135/spl deg/C on response linearity, sensitivity (span), and the resistance at zero pressure R/sub 0/ (offset) have been established for a commercial MIM composition. No change in linearity, sensitivity, and offset was observed up to 10/sup 4/ cycles. After 10/sup 6/ cycles the offset and sensitivity changed by less than 1% and 0.5%, respectively. Other parameters remained unchanged. The results are analyzed in terms of conduction models of this system.