Development of micromechanical and optical devices incorporating deposited PZT films

Abstract

This paper reports the results of a 3 year Brite-Euram (III) programme aimed at extending the functionality of micromechanical and optical devices utilising both thin and thick film PZT technologies: a oscillatory gyroscope with a resolution of 0.2°/s, signal bandwidth of 30Hz @-3dB and dimensions of 20–25 mm², a valve-less diffuser micropump capable of 0.05ml/min. and 3.5kPa maximum flow and pressure, a planar waveguide optical switch with insertion loss <1dB and switching time <1msec, and an integrated IR detector array with NETD <100 mK. Cantilever test structures indicate that d₃₁ for these films is ∼70 pC/N. Thinner films, <1μm, have been developed for the integrated IR detector array which have a pyroelectric coefficient ∼250μC/m²/K and F_D ∼1.5x10⁻⁵ Pa^−1/2. Laser crystallization of PZT using a pulsed excimer laser system has been successfully demonstrated. This is particularly significant for integration of PZT with active circuitry where post-processing temperatures must be kept below about 550°C.

Key Words:

• Micromechanical
• Optical
• Devices
• PZT