Taiwan Semiconductor Manufacturing Company Limited
FAST CHARGE TRANSFER FLOATING DIFFUSION REGION FOR A PHOTODETECTOR AND METHODS OF FORMING THE SAME

Abstract:

A subpixel including at least one second-conductivity-type pinned photodiode layer that forms a p-n junction with a substrate semiconductor layer, at least one floating diffusion region, and at least one transfer gate stack structure. The at least one transfer gate stack structure may at least partially laterally surround the at least one second-conductivity-type pinned photodiode layer with a total azimuthal extension angle in a range from 240 degrees to 360 degrees around a geometrical center of the second-conductivity-type pinned photodiode layer. The at least one transfer gate stack structure may include multiple edges that overlie different segments of a periphery of the at least one second-conductivity-type pinned photodiode layer, and the floating diffusion region includes a portion located between the first edge and the second edge. In addition, multiple transfer gate stack structures and multiple floating diffusion regions may be present in the subpixel.