Recent developments in research on metal-insulator-piezoelectric semiconductor transducers

The theory underlying the operation of metal-insulator-piezoelectric semiconductor (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. Tests of the structures under hydrostatic pressure further corroborate MIPS theory. 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.