Patent ID: 9570507
Date: 2017-02-14
CPC Classifications: H01L

Claim:
1. An image sensor pixel, comprising: a semiconductor layer; a photosensitive region having a second polarity disposed within the semiconductor layer to accumulate photo-generated charge; a floating node disposed within the semiconductor layer; a trench extending into the semiconductor layer between the photosensitive region and the floating node; an entrenched transfer gate disposed within the trench to control transfer of the photo-generated charge from the photosensitive region to the floating node; a well of a first polarity disposed within the semiconductor layer adjacent to the trench, wherein the floating node has the second polarity opposite the first polarity and is at least partially disposed within the well; a deep doped region of the second polarity disposed within the semiconductor layer below the photosensitive region and adjacent to the photosensitive region, wherein the well of the first polarity and the deep doped region of the second polarity interface forming a P-N junction, the well does not extend under the photosensitive region; and a punch-through stopper region of the first polarity disposed below the trench and extending entirely along the bottom of the trench and wrapping around both sides of the bottom of the trench such that the punch-through stopper region interfaces with the photosensitive region, the deep doped region, and the well.