Integrated Fast-Sensing Triple-Voltage SPAD Quenching/Resetting Circuit for Increasing PDP
In this letter we present a fast triple voltage quenching circuit (TVQC) with an integrated <inline-formula> <tex-math notation="LaTeX">$40~\mu \text{m}$ </tex-math></inline-formula> diameter single-photon avalanche diode (SPAD) in 0.35-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS. By pre-biasing the switching MOSFETs the reaction time of the TVQC is kept small, leading to a total quenching time of only 1.4 ns of which 0.61 ns are actively quenched. This short reaction time reduces the avalanche charge and therefore also the afterpulsing probability (APP). The dead time is adjustable from 7.9 ns to 200 ns, which allows further reducing the APP. Experimental verification shows an APP of 2.1% at a dead time of 30 ns. Using an integrated SPAD with a thick absorption zone allows achieving a photon detection probability (PDP) of 28.8% at 850 nm, while showing a peak PDP of 53.1% at 657 nm, both at 9.9 V excess bias.