Multilayer image sensor pixel structure for reducing crosstalk

A method of operating an image sensor, comprising:

• collecting charge carriers within collection regions disposed within a first N type epitaxial layer in response to light incident on the image sensor;
• generating a first field at a junction between an P type collector layer and a N type barrier layer to draw excess charge carriers generated within the N type barrier layer away from the collection regions into the P type collector layer, wherein the P type collector layer and the N type barrier layer are disposed between a substrate layer and the first N type epitaxial layer, wherein a second N type epitaxial layer is disposed between the substrate layer and the P type collector layer;
• generating a second field at a junction between the N type barrier layer and the first N type epitaxial layer to push photo-generated charge carriers generated within the first N type epitaxial layer towards the collection regions;
• and
• electrically coupling the second N type epitaxial layer to the N type barrier layer via electrical pass-throughs selectively disposed through the P type collector layer.