Nonsilicide source/drain pixel for 0.25-μm CMOS image sensor

A nonsilicide source/drain pixel is proposed for high performance 0.25-μm CMOS image sensor. By using organic material spin coat and etch back, silicide is only formed on poly gate which can be used as interconnection, not for source/drain region that solve the optical opaqueness and undesirably large junction leakage of silicide. The performance of MOSFET changes little due to the high sheet resistance of nonsilicide source/drain. With H
₂
annealing and double ion implanted source/drain junction, the dark current can be further reduced. The novel pixel (three transistors, 3.3 μm×3.3 μm, fill factor: 28%) shows low dark current (less than 0.5 fA per pixel at 25/spl deg/C) and high photoresponse.