Patent ID: 8212297

Claim:
A high optical efficiency CMOS image sensor comprising: a plurality of imaging pixels, each pixel including a photodiode structure on a semiconductor substrate, the photodiode structure being positioned adjacent a light-incident upper surface of the image sensor to receive incident light and generate electrical charges from the received incident light; an isolation grid surrounding the photodiode structure and defining an imaging pixel boundary, the isolation grid extending to a depth of at least the thickness of the photodiode structure, the isolation grid being configured to prevent the light incident on the pixel from penetrating through the incident pixel to an adjacent pixel; a positive diffusion plug vertically extending through at least a portion of the photodiode structure; a negative diffusion plug vertically extending into the semiconductor substrate beneath the photodiode structure and electrically communicating with the photodiode structure to transfer the electrical charges generated by the incident light in the photodiode structure to a charge collecting region of the image sensor positioned within the semiconductor substrate; pixel circuitry for controlling charge transfer from the photodiode structure to image readout circuitry, the pixel circuitry being positioned beneath the photodiode structure with at least a portion of the pixel circuitry being formed within the semiconductor substrate.