Investigation of MEMS Piezoelectric Transformer with PVDF Thin Layer

Abstract

This paper presents the results of experimental work on thin piezoelectric polyvinylidene fluoride (PVDF) film, used as active layer in piezoelectric transformer. PVDF film was deposited by spray deposition technique on flexible polyethylene terephthalate (PET) substrate and its thickness was measured to be 2 μm. Aluminum (Al) bottom and top contacts were deposited by vacuum thermal evaporation. The transfer function of the transformer was measured at different frequencies in the range 50 Hz – 4 MHz. It was observed that at input frequency of 1 MHz, the transfer function started to decrease, which supposed low-frequency AC/AC transformer. Dielectric losses, which characterize piezoelectric devices’ quality, were less that 0.09 in the whole frequency range. This is proof for the efficient energy conversion and stable operation of the microstructure. The work shows that the PVDF transformer performance is comparable to the existing piezoceramic based transformers, which however suffer of high dielectric losses, signal distortions and relatively low boundary frequency.