Avalanche Photodiode Having Edge Breakdown Suppression

The present disclosure relates to an avalanche photodiode having edge breakdown suppression. The photodiode comprises a p contact and an n contact, as well as a plurality of device layers disposed between the p contact and the n contact. The device layers include, in order from the p contact to the n contact, a primary well, a decoupler layer, a multiplication layer, a charge sheet, an absorption layer, and a substrate. The layers are constructed so as to have particular volumes of charge which affects the order in which they deplete. With the preferred order of depletion, the multiplication layer will deplete before the decoupler layer and the decoupler layer will deplete before the charge sheet when a negative bias is applied to the avalanche photodiode. This results in a joint opening effect within the avalanche photodiode which effectively suppresses edge breakdown.Georgia Tech Research Corporatio

InGaAs/AlGaAsSb avalanche photodiode with high gain - bandwidth product

Increasing reliance on the Internet places greater and greater demands for high -speed optical communication systems. Increasing their data transfer rate allows more data to be transferred over existing links. With optical receivers being essential to all optical links, bandwidth performance of key components in receivers, such as avalanche photodiodes (APDs), must be improved. The APDs rely on In0.53Ga0.47As (grown lattice-matched to InP substrates) to efficiently absorb and detect the optical signals with 1310 or 1550 nm wavelength, the optimal wavelengths of operation for these optical links. Thus developing InP -compatible APDs with high gain-bandwidth product (GBP) is important to the overall effort of increasing optical links’ data transfer rate. Here we demonstrate a novel InGaAs/AlGaAsSb APD, grown on an InP substrate, with a GBP of 424 GHz, the highest value reported for InP -compatible APDs, which is clearly applicable to future optical communication systems at or above 10 Gb/s

Nanoscale III-V Semiconductor Photodetectors for High-Speed Optical Communications

Nanophotonics involves the study of the behavior of light on nanometer scale. Modern nanoscale semiconductor photodetectors are important building blocks for high-speed optical communications. In this chapter, we review the state-of-the-art 2.5G, 10G, and 25G avalanche photodiodes (APDs) that are available in commercial applications. We discuss the key device parameters, including avalanche breakdown voltage, dark current, temperature dependence, bandwidth, and sensitivity. We also present reliability analysis on wear-out degradation and optical/electrical overload stress. We discuss the reliability challenges of nanoscale photodetectors associated with device miniaturization for the future. The reliability aspects in terms of high electric field, Joule heating, and geometry inhomogeneity are highlighted

Modeling and engineering impact ionization in avalanche photodiodes for near and mid infrared applications

Avalanche photodiodes (APDs) are the preferred photodetector in many applications in which low light levels need to be detected. The reason why APDs are important in such applications is due to their internal gain, which improves the APD\u27s sensitivity. Compared to receivers based on PIN photodiodes, which do not present internal gain, APD-based receivers achieve 5-10 dB improved sensitivity. The origin of the APD\u27s internal gain is the impact ionization process. However, due to the stochastic nature of the impact ionization process the multiplication gain comes at the expense of extra noise. This multiplication noise is called the excess noise, and it is a measure of the gain uncertainty. In addition, as the multiplication gain increases the buildup time, which is the time required for all the impact ionizations to complete, also increases. Thus, for a given multiplication gain the buildup time limits the bandwidth of the APD. The main challenge for state-of-the-art APDs, operating in linear and Geiger modes, is to achieve higher operating speeds. For application in which the APD is operated in linear mode the limited speed of APD-based receivers have limited their use in systems that operate at 2.5 and 10 Gbps. However, to meet the demand of the exponential growth in data transfer, the telecommunication industry has been moving toward 40-Gbps and 100-Gbps protocols for their core fiber-optic backbone networks alongside the existing 10-Gbps infrastructure operating at the low-loss wavelength of 1.55 microns. Moreover, the fast progress on quantum communications requires Geiger-mode APDs to operate at higher repetition rates. Currently, Geiger-mode APDs are limited to operate at detection rates of about 20 MHz. In addition, there has been relatively little work on infrared APDs, although there are many applications in remote sensing, medical imaging, and environmental monitoring. In particular, there is no GaAs-based APD operating in Geiger mode beyond 2 microns. This dissertation provides theoretical analysis and experimental exploration of APDs working in linear and Geiger modes in the near infrared (NIR) and mid-infrared (MIR) ranges of wavelength. This research effort is geared to address the aforementioned current challenges of the state-of-the-art APD technology. In the theoretical part of this work the focus is on the development of new theoretical methods that allow us to model, understand, and characterize avalanche photodiodes working in linear and Geiger modes. The objective is that the developed methods help the design and optimization of high performance, high speed APDs. The experimental part of this research effort consists of the design, fabrication and characterization of a novel mid-infrared sensor, based on GaAs technology, called the quantum-dot avalanche photodiode (QDAP). The main motivation for the QDAP is to exploit its potential of working in Geiger mode regime, which can be utilized for single-photon detection. In addition, the QDAP represents the first GaAs-based APD operating in the mid infrared range of wavelength

光フェーズドアレイ素子の高出力化に向けた半導体光増幅器の設計と試作

学位の種別: 修士University of Tokyo(東京大学

High performance planar germanium-on-silicon single-photon avalanche diode detectors

Single-photon detection has emerged as a method of choice for ultra-sensitive measurements of picosecond optical transients. In the short-wave infrared, semiconductor-based single-photon detectors typically exhibit relatively poor performance compared with all-silicon devices operating at shorter wavelengths. Here we show a new generation of planar germanium-on-silicon (Ge-on-Si) single-photon avalanche diode (SPAD) detectors for short-wave infrared operation. This planar geometry has enabled a significant step-change in performance, demonstrating single-photon detection efficiency of 38% at 125 K at a wavelength of 1310 nm, and a fifty-fold improvement in noise equivalent power compared with optimised mesa geometry SPADs. In comparison with InGaAs/InP devices, Ge-on-Si SPADs exhibit considerably reduced afterpulsing effects. These results, utilising the inexpensive Ge-on-Si platform, provide a route towards large arrays of efficient, high data rate Ge-on-Si SPADs for use in eye-safe automotive LIDAR and future quantum technology applications

Negative feedback avalanche diode

A single-photon avalanche detector is disclosed that is operable at wavelengths greater than 1000 nm and at operating speeds greater than 10 MHz. The single-photon avalanche detector comprises a thin-film resistor and avalanche photodiode that are monolithically integrated such that little or no additional capacitance is associated with the addition of the resistor

Dependence of the Performance of Single Photon Avalanche Diodes on the Multiplication Region Width

The dependence of the performance of separate-absorption-multiplication (SAM) single-photon avalanche diodes (SPADs) on the width of the multiplication region is theoretically investigated. The theory is applied to SAM SPADs with InP homojunction multiplication regions and InAlAs-InP heterojunction multiplication regions. In both cases the absorber layer is InGaAs. Two scenarios for the dark counts are considered: (i) low-temperature operation, when the number of dark carriers is dominated by field-assisted mechanisms of band-to-band tunneling and tunneling through defects; and (ii) room-temperature operation, when the number of dark carriers in the multiplication region is dominated by the generation/recombination mechanism. The analysis utilizes a generalized theory for breakdown probability, which takes into account the random locations where dark and photogenerated carriers are produced in each layer. Depending upon the detector temperature, as the width of the multiplication region is increased the effects from the reduction in the number of dark carriers due to field-assisted generation mechanisms are counteracted by the effects from the elevation in the number of generation/recombination dark carriers. Thus, there exists an optimal width of the multiplication region that achieves the best performance of the SPAD

Generation of high speed polarization modulated data using a monolithically integrated device

We report on the generation of high speed polarization modulated data via direct electrical binary data injection to the phase shifter section of a monolithically integrated laser diode integrated with a polarization controller. The device is fabricated on standard InP/AlGaInAs multiple quantum-well material and consists of a semiconductor laser, a passive polarization mode convertor and an active differential phase-shifter section. We demonstrate the generation of 300 Mbit/s Polarization Shift Keyed data