Potential Engineering to Enhance Transfer Characteristics of Advanced CIS Pixel based on VTG - FDTI scheme

The transfer characteristics of the three different CMOS image sensor (CIS) pixel schemes; the vertical transfer gate (VTG) with the front-side deep trench isolation (FDTI), the VTG with the back-side deep trench isolation (BDTI), and the planar transfer gate (PTG) with the BDTI are rigorously studied with 3D TCAD simulation. The electrical potential profiles of photo-diode (PD) region are optimized in terms of full well capacity (FWC) and transfer characteristics for each scheme. The simulated blooming margin potentials are well matched to the experimental blooming signal. According to our TCAD analysis, the VTG with the FDTI scheme showed high full FWC characteristics compared to the PTG with the BDTI and the VTG with the BDTI.