Novel processing of high aspect ratio 1-3 structures of high density PZT

A new process for the fabrication of fine scale, high aspect ratio PZT 1-3 composite structures has been developed. In this process, lost mold technique is utilized with a Si mold prepared by deep reactive ion etching (RIE). Due to the high strength and high melting point of Si, PZT sintering under high pressures without removing the mold becomes possible, leading to structures of highly condensed PZT in the precise shape of the mold. The typical PZT structures in this work are periodically arrayed rods 16 /spl mu/m in diameter, 100 /spl mu/m in height, resulting in an aspect ratio higher than six. The fabricated structures are to be applied to high resolution micro-ultrasonic transducers in the frequency range of 20 MHz for medical purpose.