A Method to Improve the Quantum Efficiency of the 4T-APS Pixel

By adjusting concentration of the P+layer in Pinned photodiode and Vt implant,sub-threshold leakage of the transfer gate in CMOS image sensor is reduced,and full well capacity and quantum efficiency of the pixel are improved.Simulation is performed with TCAD tools.The results show that the method is effective.Full well capacity could be raised from 3500e- to 7900e- and quantum efficiency for 550 nm incident light could be increased by 27.8%.