We present a custom CMOS IC with a buried double junction (BDJ) photodiode to detect and process the optical signal, eliminating the need for any off-chip optical filters. The on-chip signal processing circuitry improves the desired signal extraction from the optical background noise. Since the IC is manufactured using standard commercial fabrication processes with no post-processing necessary, the system can ultimately be low cost to fabricate. Additionally, because of the CMOS integration, it will consume little power when operating, and even less during stand-by.
Keywords: CMOS photodetectors; DNA–CTMA sensor; Filterless color detection; Oxygen sensor.