Electrical Performance of Metal-Insulator-Piezoelectric Semiconductor Transducers

Abstract
The theory underlying the operation of metal‐insulator‐piezoelectric (MIPS) electromechanical transducers is verified experimentally for time‐varying loads on devices made from CdS piezoelectric film materials. Experimental transducers exhibit sensitivities of the same order as those observed under static loading within times shorter than one microsecond after the application of mechanical stress. The frequency limitations for the transducer appear to be determined by the electrical properties of the MOS structure. The MIPS effect is demonstrated experimentally in CdSe transducers. Transducers fabricated on a flexible polyimide film are described, and a microphone embodying this construction is discussed. Transducers made with CdS films have properties which are more reproducible than are obtained from transducers using CdSe films. X‐ray studies show this result to be linked to crystal structure in the semiconductor layers.