Negative feedback avalanche diodes for near-infrared single-photon detection

Abstract

In recent years significant progress has been made in near-infrared single photon detection using Geiger-mode InPbased single photon avalanche diodes (SPADs). A more detailed understanding of these detectors with regard to device design, material growth and device fabrication has led to continual performance improvements. A variety of circuits for enabling SPAD Geiger-mode operation have been proposed and demonstrated as well. However, due to the inherent positive feedback nature of the avalanche process, Geiger-mode SPADs are constrained by certain performance limitations, particularly with regard to counting rate and the absence of photon number resolution. These limitations hinder the use of SPADs in certain applications. By incorporating a negative feedback mechanism into InP-based SPADs, these SPAD performance limitations can be overcome. In this paper, we present a negative feedback avalanche diode (NFAD), which is formed by monolithically integrating a passive negative feedback element with a highperformance InP-based SPAD. We describe the design and operation of the NFAD device, along with basic characteristics such as pulse response and quenching dynamics, as well as the dependence of these characteristics on excess bias voltage and input photon number. We will also review the results of near-infrared single photon counting performance for fundamental performance parameters such as photon detection efficiency, dark count rate, and afterpulsing.

Invited Review Article: Single-photon sources and detectors

“…This scheme, with the load resistor integrated with the SPAD, has been referred to as a negative-feedback avalanche diode (NFAD) to distinguish it from a SPAD with hybrid passive quench circuitry. 289 In addition, because of the compact design, NFAD arrays can be implemented where the detectors are in parallel and the output pulse amplitude provides some photon-number resolution, as each NFAD can fire and recover independently. NFADs have been implemented with InP diodes with efficiencies of 3% to 7% at 1.5 μm and pulse durations of 30 ns to 100 ns, and maximum count rates could extend as high as 10 MHz.…”

Progress in self-quenching InP-based single photon detectors

“…(The magnitude of the excess bias V ex will be dictated by operational targets for PDE since PDE increases with larger V ex .) Moreover, as we describe below, we have seen evidence from initial experiments [17] of the potential for limiting the current flow per avalanche to even less than C d × V ex , and we hypothesize that because of sufficiently large negative feedback, we are achieving avalanche quenching with only partial discharge of the diode depletion capacitance C d .…”

Single photon avalanche detectors: prospects of new quenching and gain mechanisms

“…1 that the NFAD reduces the total charge triggered by a single photon, which is defined as Geiger-mode gain as opposed to traditional gain defined by the intensity ratio between the output and input signal. Despite the reduced amount of charge or Geiger-mode gain, however, it was found that afterpulsing effects remain a limiting factor for NFAD devices [21,28].…”

“…2.8 MΩ) passive quenching is shown to make the total device charge (Geiger-mode gain) relatively independent of the overbias, and a lower amount of charge (10 6 ) with larger quenching resistance helps reduce the afterpulsing rate compared to lower resistance device operating at a higher amount of charge (mid 10 6 to 10 7 ), as explained next. From [28].…”

“…Negative feedback combats the noise limitation of APDs by reducing the excess noise factor [28]. Excess noise arises due to the statistical nature of impact ionisation, and increases when the gain variation about the mean gain increases.…”