Avalanche Transients of Thick 0.35 µm CMOS Single-Photon Avalanche Diodes

Abstract

Two types of single-photon avalanche diodes (SPADs) with different diameters are investigated regarding their avalanche behavior. SPAD type A was designed in standard 0.35-µm complementary metal-oxide-semiconductor (CMOS) including a 12-µm thick p- epi-layer with diameters of 50, 100, 200, and 400 µm; and type B was implemented in the high-voltage (HV) line of this process with diameters of 48.2 and 98.2 µm. Each SPAD is wire-bonded to a 0.35-µm CMOS clocked gating chip, which controls charge up to a maximum 6.6-V excess bias, active, and quench phase as well as readout during one clock period. Measurements of the cathode voltage after photon hits at SPAD type A resulted in fall times (80 to 20%) of 10.2 ns for the 50-µm diameter SPAD for an excess bias of 4.2 V and 3.45 ns for the 200-µm diameter device for an excess bias of 4.26 V. For type B, fall times of 8 ns for 48.2-µm diameter and 5.4-V excess bias as well as 2 ns for 98.2-µm diameter and 5.9-V excess bias were determined. In measuring the whole capacitance at the cathode of the SPAD with gating chip connected, the avalanche currents through the detector were calculated. This resulted in peak avalanche currents of, e.g., 1.19 mA for the 100-µm SPAD type A and 1.64 mA for the 98.2-µm SPAD type B for an excess bias of 5 and 4.9 V, respectively.

Cascoded Active Quencher for SPADs With Bipolar Differential Amplifier in 0.35 μm BiCMOS

“…The more charge is passing the SPAD, the more deep-level traps may be occupied, which increases the APP due to a larger probability of a later release of a charge carrier. According to [34] for thick SPADs in the same technology, the rise of an avalanche current to its maximum is quite slow and needs more than 2ns due to its low-doped epi layer when comparing it with thin SPADs in the literature. This is advantageous, because with fast electronics the duration of charge flow through the SPAD can be limited.…”

Noise and Breakdown Characterization of SPAD Detectors with Time-Gated Photon-Counting Operation

“…On the other hand, the epi layer results in a reduction of the avalanche current and speed. Transient measurements on the cathode of off-chip SPADs of a similar type and size that were bonded to the same circuit (see Goll et al [ 23 ]) revealed a fall time during avalanche of the cathode voltage to a breakdown level of approximately 10 ns, but this includes an additional load of two-times the parasitic capacitance of a pad and the input capacitance of the RF probe. Post-layout simulation shown an overall load capacitance of approximately 300 fF at the cathode of the on-chip SPAD in comparison to an estimated 700 fF load for the measured off-chip one.…”

Editorial for the Special Issue on Miniaturized Silicon Photodetectors: New Perspectives and Applications

“…Silicon (Si) technologies provide an excellent platform for monolithically integrating both photonic [ 1 ] and microelectronic [ 2 ] functionalities in the same substrate. In the last few years, a variety of passive and active Si photonic and optoelectronic devices have been reported, in particular in the field of photodetection [ 3 , 4 , 5 ] where new effects and structures have been proposed.…”

“…The reported responsivity increases by increasing the bias voltage and at 7V maximum values of about 100, 70 and 10 mA/W at 1200, 1500 and 1800 nm, have been reported, respectively. The paper of Goll et al investigates the discharge mechanism of single-photon avalanche diodes (SPADs) designed in 0.35 μm CMOS technology [ 2 ]. Indeed, after the avalanche has been triggered, the SPAD cathode–anode voltage reaches the breakdown voltage with a time that has been measured by the authors.…”