Passivation issues in active pixel CMOS image sensors

Most of the integrated circuit industry follows a final passivation process which consists of a low temperature passivation layer deposition and a thermal anneal. This two step process is particularly relevant in CMOS imagers where the dark current is a major issue. This work shows that passivation material plays an important role in the device performance. We measured H diffusion through the final silicon nitride layer and we compare these results with the material properties and passivation efficiency.