Patent ID: 7960768

Claim:
A three-dimensional pixel array comprising: a plurality of groups of pixels, each group including pixels formed in the array, and comprising at least a first layer and a second layer arranged in parallel with the first layer, the first and second layers comprising respective portions of first and second semiconductor wafers, each wafer including at least two vertically separated conductive layers, wherein the first layer of each pixel group comprises: a plurality of photosensitive elements, one per pixel in the group; a plurality of transfer gates, one per pixel in the group; a plurality of floating diffusion regions, each photosensitive element in the group coupled to one of the plurality of floating diffusion regions via a respective one of the transfer gates; and a plurality of transfer gate lines, at least one transfer gate line being connected to each respective transfer gate in each group of pixels; and wherein the second layer of each pixel group comprises at least a reset transistor for each group and a source follower transistor for each group, the reset transistor and the source follower transistor in the second layer being coupled to each of the plurality of floating diffusion regions in the corresponding first layer of the pixel group.