Characterization of standard CMOS compatible photodiodes and pixels for Lab-on-Chip devices

High quality CMOS image sensors are of great importance for LoC - Lab-on-Chip devices based on optical measurements. The main target in these devices is to minimize the cost and area while achieving a good resolution. The performance parameters of image sensor pixels and CMOS compatible photodiodes depend on the size, type and the geometry of the photodiode layout and varies for each technology. In this study, we present a comparative analysis of CMOS compatible photodiode types at different areas. The results have shown n-well/p-sub type photodiode with 5×5 μm
²
diffusion area achieves the highest sensitivity (69.81 × 10
¹²
V.s
^-1
.cm
^-2
/W.cm
^-2
) and with 40 × 40 μm
²
diffusion area, highest SNR - Signal-to-Noise Ratio (72.26dB) at 630 nm, while the p
⁺
/n-well/p-sub type photodiode with 40 × 40 μm
²
diffusion area results in highest responsivity (0.466 A. cm
^-2
/W.cm
^-2
) at the same wavelength.