Photodiode gate dielectric protection layer

An active pixel sensor (APS), comprising:

• a photodetector disposed within a semiconductor substrate;
• a gate dielectric layer disposed over the semiconductor substrate;
• a plurality of gate structures disposed over the gate dielectric layer;
• and
• a gate dielectric protection layer comprising an oxide layer, a silicon nitride layer, or a high-k dielectric material, wherein the gate dielectric protection layer is disposed over the gate dielectric layer at a first location overlying the photodetector and at a second location extending from a first position on a first sidewall of a first one of the plurality of gate structures to a second position on a second sidewall of a second one of the plurality of gate structures.

A method of forming an active pixel sensor, comprising:

• providing a semiconductor substrate having a photodetector;
• forming a gate dielectric layer over the semiconductor substrate;
• selectively forming a plurality of gate structures comprising a gate material over the gate dielectric layer;
• forming sidewalls spacers flanking sides of the plurality of gate structures;
• and
• forming a gate dielectric protection layer over the gate dielectric layer at a first location overlying the photodetector and at a second location extending from a first position between a first sidewall spacer flanking a first one of the plurality of gate structures and the gate dielectric layer to a second position between a second sidewall spacer flanking a second one of the plurality of gate structures and the gate dielectric layer.