A statistical evaluation of low frequency noise of in-pixel source follower-equivalent transistors with various channel types and body bias

Both static and low frequency temporal noise characteristics were statistically evaluated for in-pixel source followerequivalent transistors with various channel types and body bias conditions. The evaluated transistor types were surface channel (SC) and buried channel (BC) transistors with or without isolated wells. The gate width/length of the evaluated transistors was 0.32/0.32 μm/μm and the gate oxide thickness was 7.6 nm. The BC transistors without isolated well exhibit noise distribution having a much lower noise level and a steeper slope compared to the SC transistors. For the BC transistors with isolated wells without body bias, the noise level increased compared to the BC transistors with body bias. It has been confirmed that the amplitude of random telegraph noise has a correlation to subthreshold swing factor (SS) for both BC and SC transistors. The increase of the noise level of BC transistors without body bias is due to the increase of the SS originated from a stronger short channel effect.