Avalanche-Area Dependence of Gain in Passive-Quenched Single-Photon Avalanche Diodes by Multiple-Photon Injection

• Published in: IEEE transactions on electron devices Vol. 65; no. 6; pp. 2525 - 2530
• Main Authors: Kawata, Go, Sasaki, Keita, Hasegawa, Ray
• Format: Journal Article
• Language: English
• Published: IEEE 01.06.2018
• Subjects: Avalanche photodiodes; avalanche-area dependence; Capacitance; Histograms; Junctions; multiple-photon injection; passive-quenched single-photon avalanche diodes (PQ-SPADs); Photonics; picosecond pulse laser; Radiation effects; Semiconductor lasers; single-photon gain (SPG); Voltage control
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2018.2825995

It is widely believed that the single-photon gain (SPG) of passive-quenched single-photon avalanche diodes (PQ-SPADs) is given by the product of the junction capacitance (<inline-formula> <tex-math notation="LaTeX">{C}_{d} </tex-math></inline-formula>) and the overvoltage (<inline-formula> <tex-math notation="LaTeX">{V}_{\textsf {ov}} </tex-math></inline-formula>) applied to the SPAD and that this gain remains constant even under multiple-photon injection. In this paper, we show that these are not always true. We found that the SPG of PQ-SPADs increases with increasing irradiation power of a picosecond pulse laser. This result is understood by considering that the avalanche area generated by a single-avalanche trigger is smaller than the active area of the diode, and that multiple-photon injection induces multiple-avalanche triggers in the depletion layer resulting in a variation in the avalanche area within the junction. Numerical transient simulation using a 1-D avalanche diode model coupled with 2-D junction capacitance reveals that the SPG increases from <inline-formula> <tex-math notation="LaTeX">{C}_{d}{V}_{\textsf {ov}} </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">2{C}_{d} {V}_{\textsf {ov}} </tex-math></inline-formula> as the ratio of the avalanche area to diode active area increases.