Quantum Efficiency Enhancement by Optimizing BST Design for NIR CMOS Sensor

We demonstrate the quantum efficiency enhancement by using the optimized BST (backside scattered technology) structures for NIR (near-infrared) BSI (backside-illuminated CMOS image sensor). Two type BSTs with different structures are developed for NIR BSI with a cell size of 2.0 um. By using a field-shaped BST, a quantum efficiency of 36.6% at 850 nm and 23.0% at 940 nm was obtained, and using a meter-shaped BST, the quantum efficiency improved to 47.2% at 850 nm and 28.2% at 940 nm.