Modeling of a thin film pyroelectric pixel: Steady state results

Abstract

Pyroelectric thin films are receiving increasing attention for the next generation of integrated room temperature uncooled IR arrays. In this study, steady state modeling of a pixel consisting of black absorber, pyroelectric, Pt, TiOz, SiOl and SI are performed. Thermal conduction and radiative transfer are assumed to take place across this stack and at the Si substrateair interface respectively. The effects of individual film thickness, IR chopping frequency, thermal conductivity of the thermal barrier layer and substrate thickness on pyroelectric responsivity are evaluated. At low chopping frequencies, large thermal isolation is crucial to obtain optimal pyroelectric responsivity but at high frequencies, the pyroelectric response is independent of thermal isolation. Large responsivities are also obtained by using thin Si substrates. The modeling also considers air bridge structures, typically used in microelectromechanical devices.