Charge Domain Type 2.2um BSI Global ShuĴer Pixel with Dual Depth DTI Produced by Thick-Film Epitaxial Process

We developed a 2.2um Backside Illuminated (BSI) Global Shutter (GS) pixel with true charge-domain Correlated Dou-ble Sampling (CDS). A thick-film epitaxial deep DTI (Deep Trench Isolation) process was implemented to enhance 1/PLS (Parasitic Light Sensitivity) using a dual depth DTI structure. The thickness of the epitaxial substrate was 8.5 um. This structure was designed using optical simulation. By using a thick epitaxial substrate, it is possible to reduce the amount of light that reaches the memory node. Dual-depth DTI, which shallows the DTI depth on the readout side, makes it possible to read signals from the PD to the memory node smoothly. To achieve this structure, we developed a process for thick epitaxial substrate, and the dual-depth DTI can be fabricated with a single mask. This newly developed pixel rep-resents the smallest ever charge-domain GS pixel to date. Despite its compact size, this pixel achieved high QE (83%) and 1/PLS of over 10,000. The pixel maintains 80% of its peak QE at ±15 degrees. 1/PLS is stable even when the F# is small.