A new double multiplication region method to design high sensitivity and wide spectrum SPADs in standard CMOS technologies

Designing SPADs with high sensitivity in a wide wavelength range is crucial since the applications utilizing SPAD-based sensors target different parts of the spectrum. Here, we introduce a novel technique to achieve a wider sensitivity spectrum through the insertion of a second multiplication region into the depletion region. Thanks to the proposed method, at 5.5 V excess bias voltage, the fabricated devices achieved a PDP of 78% peak at 500 nm and 25.5% at 850 nm wavelength. At the same excess bias, we measured a normalized noise of 3.7 cps/μm² and a jitter of 165 ps at 517 nm FWHM.