Chopperless-operated dielectric bolometer mode of infrared image sensor with ferroelectric BST film using improved operation

Proposes a new type of simple detector pixel circuit and device structure for application of dielectric bolometer mode (DB) of IR image sensor, which has merits in uncooled operation, chopperless operation, low power dissipation, and high-sensitivity. We have successfully developed techniques of supply-voltage to the detector and a stable Ba _1-xSr_xTiO₃ (BST) thin film with large temperature coefficient of dielectric constant (TCD) as an IR detecting material, in order to stabilize the output level and improve the IR sensitivity. Also, a stress-balanced membrane for thermally isolated structure as an IR detector and resultant sensor arrays monolithically integrated with Si readout were developed. As a result, the stabilities in both TCD and output level have significantly improved and enabled us to obtain a fairly large IR detectivity, where best R_v and D* were about 1.2 kV/W and 2.9 × 10⁸ cmHz ^1/2/W, respectively