léopold virot - Academia.edu (original) (raw)

$Research paper thumbnail of D{\'e}veloppement de photodiodes {\`a} avalanche en Ge sur Si pour la d{\'e}tection faible signal et grande vitesse$

2022 IEEE Photonics Conference (IPC)

Afin d’adresser la problématique liée aux limitations des interconnections métalliques en termes ... more Afin d’adresser la problématique liée aux limitations des interconnections métalliques en termes de débits notamment, la photonique Si s’est imposée comme une technologie de choix. Un des composants de base des circuits photonique Si est le photodétecteur : Il permet de convertir un signal optique en signal électrique. Les photodétecteurs à base de Ge sur Si ont montré leur potentiel et offrent la meilleure alternative aux photodétecteurs III-V, pour une intégration dans les circuits photoniques Si.Dans ce contexte, les photodiodes à base de Ge su Si ont été étudiées. L’optimisation des photodiodes p-i-n a permis l’obtention de résultats à l’état de l’art. Une nouvelle approche utilisant une double hétéro-jonction latérale Si/Ge/Si a été proposée afin d’augmenter la responsivité mais aussi afin de proposer une meilleure solution d’intégration, avec les modulateurs Si notamment. Pour augmenter encore la sensibilité des récepteurs, l’utilisation de photodiodes à avalanche est cependan...

2021 IEEE 17th International Conference on Group IV Photonics (GFP), 2021

Optical photodetectors are at the forefront of integrated photonics research as fundamental build... more Optical photodetectors are at the forefront of integrated photonics research as fundamental building blocks for optoelectronic systems and communication links. However, chip-integrated photodetectors with improved performances constitute on-going challenges for such applications. We present recent progress in high-speed silicon-germanium photodetectors fabricated on silicon-foundry-compatible platforms.

Integrated Optics: Design, Devices, Systems and Applications VI, 2021

Integrated silicon nanophotonics has progressed a lot over past decades with great promises for m... more Integrated silicon nanophotonics has progressed a lot over past decades with great promises for many surging applications in optoelectronics, information and communication technologies, sensing or health monitoring. Enabling low-cost, dense integration, and compatibility with modern semiconductor nanofabrication processes, silicon nanophotonics deliver compact and high-performance devices on single chips. A variety of nanophotonic functionalities, both passive and active, are nowadays available on semiconductor substrates, leveraging the maturity of open-access silicon foundries and epitaxial germanium integration. It encompasses essential functions such as light generation and amplification, fast electro-optical modulation, and reliable conversion of optical into electrical signals. Germaniumbased optical photodetectors are main building blocks within the library of integrated silicon nanophotonics, with performances that are nowadays on par with their III-V-based counterparts. Germanium photodetectors integrated at the end of waveguides are attractive for next-generation on-chip interconnections, because of their compactness, bandwidth and speed, energy consumption and cost. In this work, we present our latest advances on silicon-germanium p-i-n waveguide-integrated photodetectors based on lateral silicon-germanium-silicon heterojunctions. Our hetero-structured photodetectors were fabricated on top of 200-mm silicon-on-insulator substrates using industrial-scale fabrication processes compatible with complementary metal-oxide-semiconductor technology. Silicon-germanium p-i-n photodetectors operated under low bias voltages exhibited low dark-currents (~100 nA), cut-off frequencies beyond 50 GHz, and photo-responsivities of about 1.2 A/W. Photodetector sensitivities of -14 dBm and -11 dBm were achieved for communication data rates of 10 Gbps and 25 Gbps, respectively. P-i-n photodetectors with lateral heterojunction operated in an avalanche regime offered an additional degree of freedom to improve device performances. High-speed and low-noise characteristics were obtained in our p-i-n photodetectors upon avalanche operation, with a gain-bandwidth product of 210 GHz and a low carrier impact ionization ratio of about 0.25. The measured sensitivity of avalancheoperated devices was -11 dBm for 40 Gbps signal detection. As demonstrated in the reported achievements, heterostructured p-i-n photodetectors are thus suitable communication devices in future intra-data center links or high-speed optical interconnects.

Photonic Instrumentation Engineering IX, 2022

Integrated Optics: Devices, Materials, and Technologies XXVI, 2022

Silicon Photonics XV, 2020

In this paper, we present a statistical characterization results for a high-speed germanium photo... more In this paper, we present a statistical characterization results for a high-speed germanium photo-detector structure that calls for no additional process steps than a regular modulator. The photodiodes in question are waveguide PIN SiGeSi photodiodes with targeted bandwidths on the range of 50GHz and a responsivity of more than 0.8A/W at 1310nm. The design logic, mainly intended to reduce the transit time while conserving a high detection area will be explained in details.

2016 IEEE 13th International Conference on Group IV Photonics (GFP), 2016

Silicon photonics is becoming a technology of choice for optical communications. Compatibility wi... more Silicon photonics is becoming a technology of choice for optical communications. Compatibility with cmos manufacturing process is one key of success since it allows taking advantage of the production capacities of foundries; i.e. big volume and low cost manufacturability [1]. Germanium is the ideal candidate to build the integrated high performance photodiodes needed for receiver circuits [2]. Meanwhile, pure Ge epitaxy is not common in cmos processes and its integration within a silicon platform is not straightforward. In particular, germanium is very sensitive to wet etch processes. Post Ge-epitaxy dopant activation is also difficult due to thermal budget limitations. In this work, we propose a novel photodetector architecture which is integrated in a silicon photonic platform in a cost effective and robust manner.

Integrated Optics: Devices, Materials, and Technologies XXIII, 2019

On-chip light detection is universally regarded as a key functionality that enables myriad of app... more On-chip light detection is universally regarded as a key functionality that enables myriad of applications, including optical communications, sensing, health monitoring or object recognition, to name a few. Silicon is widely used in the microelectronics industry. However, its electronics bandgap precludes the fabrication of high-performance photodetectors that operate at wavelengths longer that 1.1 µm, a spectral range harnessed by optical communication windows of low fiber attenuation and dispersion. Conversely, Germanium, a group-IV semiconductor as Silicon, with a cutoff wavelength of ~1.8 µm, yields efficient light detection at near-infrared wavelengths. Germanium-based photodetectors are mature building blocks in the library of silicon nanophotonic devices, with a low dark-current, a fast response, a high responsivity and low power consumption with an established fabrication flow. In this work, we report on the design, fabrication and operation of waveguide pin photodetectors that advantageously exploit lateral Silicon/Germanium/Silicon heterojunctions. Devices were fabricated on 200 mm silicon-on-insulator substrates using standard microelectronics production tools and processes. This photodetector architecture takes advantage of the compatibility with contact process steps of silicon modulators, thereby offering substantially reduced fabrication complexity for transmitters and receivers, while providing improved optical characteristics. More specifically, at a lowbias reverse voltage of-1 V, we experimentally achieved dark-currents lower that 10 nA, a device photo-responsivity up to 1.1 A/W, and large 3-dB opto-electrical bandwidths over 50 GHz. In addition, high-speed data rate transmission measurements via eye diagram inspection have been conducted, with pin photodetector operation at the conventional 10 Gbps up to the future 40 Gbps link speeds.

Integrated Optics: Devices, Materials, and Technologies XXIV, 2020

Owing to its low-cost, high-yield, and dense integration ability, silicon nanophotonics is a good... more Owing to its low-cost, high-yield, and dense integration ability, silicon nanophotonics is a good candidate to tackle the needs of exponentially growing communications in data centers, high-performance computers, and cloud services. Moreover, a number of nanophotonic functions are now available on a single chip, as they take advantages of siliconfoundry process maturity and epitaxial germanium integration. Optical photodetectors are key building blocks in the library of group-IV components and their performances are quite successful nowadays. In particular, silicon-germanium waveguide-integrated photodetectors are fixing new standards for next generation of on-chip interconnects in terms of compactness, speed, power consumption and cost. Indeed, conventional pin photodetectors yield good responsivities (~1 A/W in a 1.5 µm wavelength range), high bandwidths (~50 GHz), and dark currents well below 1 µA. Despite recent advances, their optical power sensitivities remain rather modest and speeds are limited to 25 Gbps only, however. Compensating for the insufficient photodetector sensitivity requires higher transmitter output powers and therefore higher energy consumption. Additional energy savings can be obtained by eliminating receiver electronics. Alternatively, an appealing approach is to exploit device structures with an internal multiplication gain to lower even more the power budget and improve energy efficiency of chip-based optical links. In this work, we report on waveguideintegrated photodetectors with lateral silicon-germanium-silicon heterojunctions. Here, we present avalanche photodetectors fabricated on 200-mm silicon-on-insulator wafers using complementary metal-oxide-semiconductorcompatible processes. Devices operate in the low-gain-regime to facilitate high-speed link operations at 1.55 µm wavelengths. An error-free signal detection was achieved at 28 Gbps, with power sensitivity of-11 dBm for 10-9 biterror-rate, which is a relevant link rate for emerging chip-scale optical interconnects.

2019 IEEE 16th International Conference on Group IV Photonics (GFP), 2019

Hetero-structured silicon-germanium-silicon photodetectors operating under low-reverse-voltages w... more Hetero-structured silicon-germanium-silicon photodetectors operating under low-reverse-voltages with high responsivity, fast response, and low dark-current levels are reported. A bit-error-rate of 10-9 is experimentally achieved for conventional data rates of 10, 20, and 25 Gbps, providing optical power sensitivities of-13.9,-12.7, and-11.3 dBm.

Extended Abstracts of the 2019 International Conference on Solid State Devices and Materials, 2019

This document provides supplementary information to the research article entitled "40 Gbps hetero... more This document provides supplementary information to the research article entitled "40 Gbps heterostructure germanium avalanche photo receiver on a silicon chip,"

We present recent results on high-speed waveguide p-in photodetectors with lateral hetero-structu... more We present recent results on high-speed waveguide p-in photodetectors with lateral hetero-structured Silicon-Germanium-Silicon (Si-Ge-Si) junctions monolithically integrated on Silicon-on-Insulator substrates. Optical photodetectors leverage a unique integration strategy, combining butt-waveguide-coupling and lateral Si-Ge-Si p-in hetero-junctions. Fabrication is then easier, more robust and fully compatible with available Si-foundry processes. Under a low-voltage operation, 1 µm wide devices have dark currents of at most 150 nA, high responsivity of 1.2 A/W, and-3dB cutoff frequency of 12 GHz. Furthermore, an errorless detection is experimentally achieved for a conventional 10 Gbps data rate, with power sensitivity down to-13.9 dBm with a bit-error-rate (BER) of 10-9. Moreover, under avalanche operation, a 0.8 µm wide p-in diode offers attractive improvements in opto-electrical performances. In particular, initial results show that device responsivity is enhanced from 0.42 A/W up t...

2017 IEEE 30th International Conference on Micro Electro Mechanical Systems (MEMS), 2017

This paper reports hollow MEMS plate oscillators for the characterization of liquid samples, with... more This paper reports hollow MEMS plate oscillators for the characterization of liquid samples, with a one-fold improvement in both Q-factor and Allan deviation compared to previous alike structures, and fluidic constriction larger than 1μm. These new characteristics make the devices amenable for the first time to liquid weighing with a 100 Hz.(g.L−1)−1 sensitivity and a few g.L−1 detection floor.

For the sub-32 nm nodes, porous SiCOH dielectrics (p-SiCOH) are integrated using dual damascene p... more For the sub-32 nm nodes, porous SiCOH dielectrics (p-SiCOH) are integrated using dual damascene patterning by etching trenches and vias directly into the porous material. Since p-SiCOH dielectrics exhibit a poor resistance to plasma treatments one challenge is to control the process conditions to minimize the plasma-induced damage. Until now Ellipsometric Porosimetry (EP) on blanket test wafers has been used to investigate the impact of plasma treatments on porous materials and demonstrated possible surface densification and hydrophobicity loss after the process steps [1]. Unfortunately the properties of vertically patterned structures, i.e. real circuits, may differ from the bottom of the trench region. Few studies have been performed on patterned structures to determine the sidewall modification while this information is critical for device performance. In this study quantitative measurements of vertically patterned porous materials will be demonstrated using the recently develope...