Analysis methodology of Deep Trench Isolation Field-Effect Passivation techniques for Image Sensors through dedicated test structures

Passivation techniques are mandatory to reduce the CMOS Image Sensors dark current from interfaces. In this work a general analysis methodology is proposed to study the Deep Trench Isolation field-effect passivation thanks to dedicated test structures. Two deep trench isolations are characterized: an electrically active trench and an innovative passive trench using charged Al2O3/SiO2 stacks. The results, validated by TCAD simulations, show that the best passivation is achieved here with the passive trench. Beyond, our approach is demonstrated to be a powerful tool for technologies and pixels developments with a fair passivation efficiency comparison through accumulation or inversion layer carrier concentrations. This work is also a first step toward dark current contribution modeling.