In this paper, the influences of the depth and width of the oxide trench isolation between pixels, pixel epitaxial layer thickness for different impurity doping concentrations, and light exposure time on electrical crosstalk are characterized in an array of pinned photodiode CMOS image sensor pixels. The simulation results show that with a proper and simultaneous selection of epitaxial layer doping concentration and epitaxial layer thickness, the electrical crosstalk at long wavelengths can be reduced above 66%. The use of oxide trench isolation depth less than pixel p-well depth leads to an increase in electrical crosstalk of more than 12%.
View Article and Find Full Text PDFIn this paper, a complete investigation and 2D simulation of electrical crosstalk in a setup with three neighboring pinned photodiode complementary metal-oxide-semiconductor (CMOS) image sensor pixels are performed. Electrical crosstalk characterization as a function of pixel size and epitaxial layer doping concentration is presented. The simulation results in constant epitaxial layer doping concentration show that the ratio of external quantum efficiency to electrical crosstalk is linear with respect to pixel size.
View Article and Find Full Text PDFImplantable image sensors have several biomedical applications due to their miniature size, light weight, and low power consumption achieved through sub-micron standard CMOS (Complementary Metal Oxide Semiconductor) technologies. The main applications are in specific cell labeling, neural activity detection, and biomedical imaging. In this paper the recent research studies on implantable CMOS image sensors for neural activity monitoring of brain are being quantified and reviewed.
View Article and Find Full Text PDFDigital silicon photomultiplier (dSiPM) is introduced for diffuse optical imaging (DOI) applications instead of conventional photomultiplier tubes and avalanche photodiodes (APDs) as a state-of-the-art detector. According to the low-level light regime in DOI applications, high sensitivity and high dynamic range (DR) image sensors are needed for DOI systems. dSiPM is proposed as a developing detector which can detect low-level lights.
View Article and Find Full Text PDFIntroduction: This paper analyses the ability of single-photon avalanche diodes (SPADs) for neural imaging. The current trend in the production of SPADs moves toward the minimum dark count rate (DCR) and maximum photon detection probability (PDP). Moreover, the jitter response which is the main measurement characteristic for the timing uncertainty is progressing.
View Article and Find Full Text PDFWe report on the first implementation of a single-photon avalanche diode (SPAD) in 90nm complementary metal oxide semiconductor (CMOS) technology. The detector features an octagonal multiplication region and a guard ring to prevent premature edge breakdown using a standard mask set exclusively. The proposed structure emerged from a systematic study aimed at miniaturization, while optimizing overall performance.
View Article and Find Full Text PDF