Back Side Illuminated, Fully Depleted, Pinned Trench Photo MOS for Imaging Applications

This paper describes a new BSI image sensor pixel using an advanced PhotoMOS structure designed with capacitive deep trench pixel-to-pixel isolation. This PhotoMOS technology is a smart alternative to the conventional implanted pinned photodiode and providing an image quality gain. Indeed the photo-gate device fabrication takes benefit from the full-depth front process MOS trench etched through a fully optimized silicon epitaxial layer and dedicated to photon absorption, signal charges collection and storage zone avoiding any implanted doping species. On top of the photo Gate device, a planar read-out transistors and a vertical transfer gate is proposed.