640x512 T2SL dual-band infrared detector and read-out circuit

T2SL(Type II Super Lattice) can be designed for response wavelength band. Because of these characteristics, it has now widely used for infrared detector material. Since it is typically grown by molecular beam epitaxy(MBE), T2SL is also used to develop dual-band detector by stacking it vertically. In this work, the performance of readout circuit(ROIC) for dual-band detector which has single bump in pixel will be presented. The developed ROIC has the format of 640 x 512 pixels with 20 μm pitch. It consists of an internal and external bias circuit that switches the dual-band T2SL infrared image sensor for selecting long-wave(LW) and mid-wave(MW) infrared responses. It also has windowing, flipping, and mirroring functions. This ROIC can output each single-band in a 60Hz frame rate, and dual-band can also be coupled sequentially at the same 60Hz frame rate. When LWIR and MWIR images were output in alternate frames, the average noise equivalent temperature difference (NETD) for each frame was measured to be less than 30 mK in the single LWIR frame and the single MWIR frame, including testing equipment. Also, power consumption of 87.18 mW was measured when outputting dual-band images at a 60 Hz frame rate at an operating temperature of 77 K cooled with liquid nitrogen. Additionally, brief detector of dual-band infrared image sensor descriptions is also included to aid understanding of the readout circuit.