SiO2/SiN Multilayer-Stack Infrared Absorber Integrated on Pb(Zr0.4,Ti0.6)O3 Film Pyroelectric Sensors on γ-Al2O3/Si Substrate

Abstract

In this study, Pb(Zr 0.4 ,Ti 0.6 )O 3 (PZT) film pyroelectric infrared sensors were fabricated on a Si substrate with a SiO 2 /SiN multilayer-stack infrared (IR) absorber and characterized. Since an IR absorber is a critical element that determines the sensitivity of IR sensors, we have proposed a multilayer-stack IR absorber based on complementary metal-oxide-semiconductor (CMOS) compatible materials for the PZT film pyroelectric sensor. We designed and fabricated a SiO 2 /SiN multilayer-stack IR absorber that possesses a broad and high IR absorptance in the wavelength range from 8 to 14 μm. The thicknesses of the SiO 2 and SiN films were designed as 550 and 850 nm, respectively, according to the calculation result of absorptance in the multilayer films. The SiO 2 /SiN multilayer-stack absorber was integrated on PZT film sensors by plasmaenhanced chemical vapor deposition, and 86% average IR absorptance was obtained in the wavelength range from 8 to 14 μm. A specific detectivity of 1.15 × 10 7 cmHz 0.5 /W was achieved at 30 Hz on the PZT film pyroelectric sensor.