ABSTRACT
Ferroelectric materials show excellent properties for silicon-based piezoelectric and pyroelectric microsensor and microactuator applications. 1 In particular, the pi ezoelectric coefficients of the perovskite ferroelectric thin films lead zirconate ti tanate (Pb(ZrcTi1 _JC)0 3 or PZT) and lead titanate (PbTi03) are approximately 1530 times larger than that of previously used non-ferroelectric materials such as aluminum nitride (AIN) and zinc oxide (ZnO). The pyroelectric properties in these ferroelectric thin films are approximately 1 0 0 times larger than in previously used non-ferroelectric (ZnO) thin films. The large piezoelectric properties of PZT are therefore ideally suited for integrated microsensor applications such as 1 ) pressure sensing, 2 2) tactile force sensing, 3 3) acceleration measurement4 and 4) a variety of sensing applications based on surface-acoustic wave (SAW) devices. 5 The large pyroelectric response of PbTi03 are ideally suited for 1) room temperature infrared detection, 6 2) hot wire anemometry7 and 3) chemical enthalpimetric detection. 8 Furthermore, the large inverse piezoelectric effect observed in ferroelectric films may be suitable for future micromechanical positioner and micromechanical motor applications. 9 1 0
Piezoelectric thin films have been used in microsensor applications over the last twenty years. When combined with silicon electronic circuitry, 11 these films form useful integrated microsensors with 1) low-noise, 2) low power dissipation and 3) compact size and minimal interconnection parasitic losses.
