PZT films for micro-pumps

A micro-pump for medical applications is being developed using organometallic derived PZT thin films and silicon micromachining technology. Critical issues include the deposition of 'thick' PZT films (1 to 2 mu m thickness), film processing compatibility with available Si/SixNy/Ta/Pt structures and the establishing of piezoelectric poling parameters. A processing technique for the preparation of thick PZT films is presented. Piezoelectric properties are characterized by both direct method using alternating compressional force and by converse method using laser interferometry. In poled films of approximately 1.0 mu m thickness, d(33) values of about 130 pC/N were measured by both direct and converse methods. Maximum d(33) constants of approximate to 200 pC/N were measured with 8 V bias voltage. Mechanical resonance was excited in a 1 cm by 1 cm silicon substrate by a 0.8 mu m thick PZT film poled at 15 V.