Image sensor with floating diffusion interconnect capacitor

摘要

An image sensor includes a pixel circuit that includes a light sensing element and a charge storage node formed in a substrate, an output element having a control electrode formed in an electrode layer above the substrate, the output element generating an output signal corresponding to charge generated by the light sensing element and held by the charge storage node, and a local metal interconnect that electrically connects the charge storage node to the control electrode. Control wirings that control operations of the pixel circuit are formed in wiring layers that are located above the electrode layer. The metal interconnect is formed in a layer that is located above the electrode layer and below a lowest one of the wiring layers such that a given one of the control wirings overlaps the metal interconnect so as to form a parallel plate capacitor in a region of overlap.

主权项

1. An image sensor, comprising:
a plurality of pixels two-dimensionally arrayed, each including a light sensing element, a charge storage node, a transfer element between the light sensing element and the storage node, an output element, and a local metal interconnect that connects the charge storage node to a control electrode of the output element, wherein the local metal interconnect forms a parallel-plate dual capacitor with a control electrode of the transfer element and with a given pixel control wiring located in an M1 wiring layer.