Piezoelectric transducer array microspeaker

Abstract

In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. The speaker is an array of micro-machined piezoelectric membranes, fabricated on silicon wafer using advanced micro-machining techniques. Each array contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT), a top electrode of 300nm and a structural layer of 50' μm made of polyimide. The wafer layout design was diced in nine chips with different array configurations, with variation of the membrane dimensions. The device was tested with different voltages obtaining good sound output levels by using only 3 V.