An APD-CMOS image sensor toward high sensitivity and wide dynamic range

We present a sensitivity-boosting technique by incorporating an avalanche photodiode into a normal photo-conversion region. Under a dark scene, an avalanche photodiode operation is selected, where the photo-electrons are multiplied up to 10 ⁵ electrons. Under a bright scene, a photodiode operation is selected, where photo-electrons in proportional to light intensity are generated in a similar way to conventional CMOS image sensors. Alternating the two operations enables wide operational range extending to dark conditions.