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Surface-micromachining techniques have been used in the fabrication of a 64/spl times/64 element PbTiO/sub 3/ pyroelectric infrared imager. Polysilicon microbridges of 1.2 /spl mu/m-thickness have been formed 0.8 /spl mu/m above the surface of a silicon wafer. Each of the 4096 polysilicon microbridges measures 50/spl times/50 /spl mu/m/sup 2/ and forms a low thermal mass support for a 30/spl times/30 /spl mu/m/sup 2/ PbTiO/sub 3/ pyroelectric capacitor with a thickness of 0.36 /spl mu/m. The air-bridge formed reduces the thermal conduction path between the detector element and substrate. An NMOS preamplifier cell is located directly beneath each microbridge element. The measured blackbody voltage responsivity at 30 Hz is 1.2/spl times/10/sup 4/ V/W. The corresponding measured normalized detectivity (unamplified) D* is 2/spl times/10/sup 8/ cm-Hz/sup 1/2/W at 30 Hz. The test chip fabricated measures 1/spl times/1 cm/sup 2/ and contains more than ten thousand transistors and 4096 micromechanical structures with integrated ferroelectric microsensors. The technique of stacking of microsensors and integrated circuits represents a new approach for achieving high-density and high-performance integrated pyroelectric microsensors through minimization of circuit to sensor interconnection with extremely small thermal crosstalk. >

The compact linear-motion piezoelectric actuator developed has relatively large displacement capabilities. It is composed of a number of parallel bars of lead zirconium titanate (PZT) connected together in a meander-line configuration so that they are mechanically in series and electrically in parallel. The polarity of the adjacent bars is arranged so that if a given bar expands under the applied voltage, the adjacent bars contract. An electromechanical model of the actuator predicted and measurements verified that stiffeners added to the basic meander line geometry significantly increased the force output without affecting the displacement versus applied voltage relationship. >

A linear stepper motor capable of submicrometer controlled movement has been constructed using the piezoelectric material lead zirconate titanate (PZT). This motor consists of a 25.4-mm*12.7-mm*1.6-mm piezoelectric driving element connected between a glider base and an attached load. The device is inset in a trench to constrain motion to one dimension. An electrode on the bottom of the glider is used with an electrode on the top of the trench to implement an electrostatic clamp. This clamp enables the stepper motor to climb slopes of up to 12 degrees , whereas without the clamp only slopes of 6 degrees or less are tolerated. A linear inertial sliding motion can be achieved by expanding and contracting the piezoelectric bar, but the addition of the electrostatic clamp enhances the movement capabilities of the glider by the periodic clamping and unclamping of the glider. Glider velocities of 5.7-476 mu m/s are measured by timing the movement of the glider over a 1.0-mm portion of the track through an optical microscope. Displacement steps of 0.07-1.1 mu m are calculated by dividing the measured glider velocity by the frequency of the applied voltage pulses. Displacement step size and glider velocity are controlled by the application of PZT extension voltages ranging from +or-(60-340) V. >