Effects of Deep Trench Isolation Shape and Microlens Radius of Curvature on Optical and Electrical crosstalk in Backside Illuminated CMOS Image Sensors

In this work, we have utilized finite difference time domain (FDTD) simulation to investigate the crosstalk behavior with the deep trench isolation (DTI) shape and radius of curvature (RoC) of microlens of pixels arrayed in a Bayer pattern. For blue illumination of 400 nm, the sum of optical and spectral crosstalk is lower for DTIs with values of Wratio is greater than 1; for green illumination of 550 nm, we got a similar result when the values of Wratio is below 1. The higher generation of electron hole pairs (EHPs) deep inside silicon (Si) causes a rise in the electrical crosstalk with larger Wratio values with blue illumination of 400nm. The optical and spectral crosstalk cumulatively increases with microlens having a higher RoC due to the wider spread of illumination overlaps with the DTI surface and eventually leaks into neighbor pixels.