Compact image sensor arrangement with read circuitry over pixel zones

摘要

An image sensor having a number of pixel zones delimited by isolation trenches, each pixel zone including a photodiode; a transfer gate associated with each of the pixel zones and arranged to transfer charge from the photodiode to a sensing node; and a read circuit for reading a voltage at one of the sensing nodes, the read circuitry including a number of transistors of which at least one is positioned at least partially over a pixel zone of the pixel zones.

主权项

1. An image sensor comprising:
a plurality of pixel zones formed in a substrate; a plurality of isolation trenches delimiting the pixel zones and separating the pixel zones from each other; a plurality of photodiodes respectively positioned in the pixel zones; a plurality of sensing nodes associated with the pixel zones; a plurality of transfer gates respectively associated with said pixel zones, each transfer gate being arranged to transfer charge from said photodiode of the associated pixel zone to one of the sensing nodes; and a read circuit for reading a voltage at the one of the sensing nodes, the read circuit including a plurality of transistors including at least one transistor that is positioned at least partially over a first pixel zone of said plurality of pixel zones, wherein said isolation trenches delimiting said pixel zones are deep trench isolations, wherein said deep trench isolations and said substrate are of equal depth and wherein said at least one transistor has a channel region bounded on at least one side by a shallow trench isolation of less depth than the deep trench isolations, wherein each transfer gate comprises a conductive column formed in an opening in the isolation trench delimiting the pixel zone associated with the transfer gate, wherein the one of the sensing nodes is also formed in said opening, adjacent to said conductive column.