Optical sensitivity and barrier property depending on ILD layers of CMOS image sensor device

As the refractive index of the passivation layer in a CMOS image sensor was increased and hence as the passivation layer became nitrided, the barrier property against contaminants was improved because of the densification of the layer. The result of the ray tracing simulation showed the improvement in cohesivity of light at the photodiode as well. However, the high refractive index of the passivation layer caused high reflection at the surface and hence a decrease in sensitivity. Moreover, with the use of ARL (Anti Reflection Layer) to control the high reflection at the Si substrate, the increase in the refractive index of ARL brought about the increase in sensitivity due to the low reflection at the Si substrate