Application of gas jet deposition method to piezoelectric thick film miniature actuator

Currently the development of piezoelectiric miniature actuators is a subject of interest in the industrial field of mobile electronic devices. Although the deposition of PZT(Pb(Zr_.52, Ti_.48)O₃) in the thickness range of 10 to 100 μm is a key technology for the realization of miniature actuators, thick films of PZT have rarely been prepared by other deposition methods for glued PZT structures. It is also difficult to obtain a thickness of less than 50 μm. This is the reason why we have designed and fabricated a two-dimensional miniature scanner actuated with a relatively thick piezoelectric layer by a recently introduced gas deposition method of ultra fine particles with a subsonic gas jet stream. A piezoelectric PZT layer, of thickness 30 microns is deposited onto a stainless steel substrate and patterned by the simple lift off method, to fabricate a bimorph type actuator beam. Mirror scanning is performed by four independent actuator beams. The device can be scanned along two axes by two independent resonant frequencies. Deflection of the fabricated scanning mirror is measured by laser interferometer and compared with the simulation results obtained by FEM (finite element method). Scanning of the laser light is also demonstrated by the fabricated device.