High-speed lateral polysilicon photodiode in standard CMOS technology

A high-performance lateral polysilicon photodiode was designed in standard 0.18 /spl mu/m CMOS technology. The device has a frequency bandwidth far in the GHz range: the measured bandwidth of the poly photodiode was 6 GHz, which figure was limited by the measurement equipment. The high intrinsic (physical) bandwidth is due to a short excess carrier lifetime. The external (electrical) bandwidth is also high because of a very small parasitic capacitance (< 0.1 pF). This is the best bandwidth performance among all reported diodes designed in a standard CMOS. The quantum efficiency of this poly photodiode is 0.2% due to the very small light sensitive diode volume. The diode active area is limited by a narrow depletion region and its depth by the technology.