Abstract: An integrated photosensing device includes a three-terminal photosensing device integrated within a photo-integrator semiconductor integrated circuit. The photosensing device includes a Metal-Oxide-Semiconductor (MOS) capacitor merged with a junction diode, both of which are integrated on a semiconductor substrate. The photo-integrator semiconductor integrated circuit includes a voltage buffer and a number of switches for configuring the photo-integrator during an operating cycle that includes three phases. The circuit resets during the first phase and integrates during the second phase. During the third phase, the circuit forces the output impedance of the photosensing device to increase such that the signal output of the circuit is boosted. Various embodiments are described for the present invention which disclose several buffer and switch configurations for buffering the output and providing the bias requirements of the photosensing device.

Abstract: A photosensing device is provided which has a photojunction structure that includes a junction of a photodiode and a body-junction of a photo-capacitor operating in an inversion mode. The photojunction structure is fabricated with standard complementary MOS (CMOS) technology features and includes an edge that is guarded against known leakage-causing hazards. In one embodiment, the photodiode junction is surrounded by the body-junction of a poly-gate MOS capacitor to form the photojunction. The photojunction can be placed deeply under a surface of the photosensing device by utilizing a deep diode diffusion to exhibit a better response at the red end of the spectrum. In another embodiment, both shallow and deep junction diodes are combined so that the photojunction has a composite depth which can be used to weight the spectral response to favor one or the other end of the light spectrum.