Thermal and electrical performance of α-Si microbolometer focal plane arrays

Abstract

Recent advances of microelectromechanical system (MEMS) technology have opened new opportunities for amorphous silicon (α-Si) microbolometer focal plane arrays (FPAs) both for military and civil applications. α-Si membrane is chosen for sensitive material of microbolometer FPAs due to its high temperature coefficient of resistance (TCR), high resistivity and good mechanical properties. However, α-Si membrane also has the disadvantage of high 1/f noise, strict preparation conditions and metastable effect. So nowadays, researches are focused on properties of α-Si membrane to gain high performance of microbolometer FPAs. Since the pulsed bias readout mode of microbolometer FPAs causes a non-steady-state of α-Si membrane during the operation, the transient thermal-electrical response process of the sensing pixel is analyzed detailedly in this paper to predict the thermal and electrical performance of α-Si microbolemeter FPAs such as responsivity, noise equivalent temperature difference (NETD), detectivity and power dissipation. Numerical simulations are presented to investigate the factor which affects the performance of α-Si microbolometer FPAs. The imaging experiment results obtained from a 320×240 α-Si microbolemeter FPA are in good agreement with the theoretical analysis. The way to improve the performance of α-Si microbolemeter FPAs is given in the end of this paper.