Patent ID: 9281331
Filing Date: 2016-03-08
CPC Classification: H01L

Claim Text:
1. An active pixel sensor (APS) comprising: a photodiode arranged in a semiconductor substrate, laterally adjacent to a vertical trench, wherein the photodiode is configured to convert incident radiation to electrical charge and to accumulate the electrical charge; a vertical-gate transfer transistor configured to selectively transfer the accumulated charge to a charge storage node for read-out, wherein the vertical-gate transfer transistor includes a dielectric layer lining the vertical trench and a vertical gate filling the vertical trench over the dielectric layer, wherein the dielectric layer has a dielectric constant exceeding that of silicon dioxide, and wherein the vertical gate extends from a point over the photodiode to a point below the photodiode; a shallow trench isolation (STI) region extending into the semiconductor substrate to a first depth, and laterally surrounding the photodiode and the vertical-gate transfer transistor; and a deep trench isolation (DTI) region extending into the semiconductor substrate to a second depth greater than the first depth, laterally surrounding the STI region, and restricted to a periphery of a multi-pixel sensor array to which the APS belongs; wherein the dielectric layer covers the STI and DTI regions and comprises an opening exposing the photodiode and source and drain regions on opposing sides of the vertical trench.