Multi-functional 0–3 composite polyimide films for microsystem applications

Abstract

The development of smart functional thin film composite polymer materials has been extensively investigated over the past decade. However, the polymers poor thermal properties have negatively impacted the manufacturing complexity resulting in limited success in microsystem applications. This paper investigates the development of microelectromechanical systems compatible flexible multi-functional 0–3 composite materials consisting of a high temperature polyimide (PI) matrix with lead zirconate titanate (PZT) and silver (Ag) nanoparticles. Microfabrication manufacturing methods were investigated to deposit the thin film composites and they were characterized with varying concentrations of nanoparticles. Piezoelectric composites with room temperature d 33,f values up to 23 pC N−1 were demonstrated. In addition, Ag-PI composites demonstrated electrical conductivity values of 11 S m−1 at room temperature. The composites maintain relatively high mechanical flexibility and temperature properties from the PI matrix. Integration of the nanoparticles in the films were validated through x-ray diffraction and scanning electron microscopy images. The PZT-PI composites demonstrated an increase in piezoelectric values under elevated temperatures up to 300 °C. Capacitor and energy harvesting devices consisting of three layers of composite films (Ag-PI/PZT-PI/Ag-PI) were microfabricated to validate the materials functionality and integration into microsystem-based devices. These novel flexible high temperature films could have wide use in next generation electronics.