Characterization of CMOS IC photodiodes using focused laser sources

The static photoresponse of CMOS based integrated circuit (IC) photodiodes is presented. Typically, a standard CMOS n-well process can support n⁺-P_sub, n_well-P_sub, and p⁺-n_well photodiode types. Each type of photodiode is characterized using one of four focused optical sources including: 1 HeNe green (λ=543 nm), 2 HeNe red (λ=633 nm), laser diode red (λ=670 mm), and 4 laser diode infrared (λ=818 nm) lasers. In general, the responsivity of the photodiodes is comparable to commercially available devices, so they are ideally suited for low-cost low-power CMOS based optoelectronic circuits