ESD characterization of planar InGaAs devices

We present a comprehensive study of ESD reliability (TLP) on planar nMOSFETs with In0.53Ga0.47As as the channel material. Two types of traps are found during ESD stress. They are formed through independent mechanisms: transient Ef-lowering induced pre-existing e-traps discharging in the gate stack and hot hole induced e-traps generation through impact ionization in the InP buffer. These two types of traps explain the observed walk-out of off-state channel leakage current as well as the two-stage current conduction phenomena in the TLP measurement. The generated e-traps are permanent and can introduce detrimental conduction current harmful to the device performance. By properly selecting the buffer material, these defects can be removed

Advances in Solid State Circuit Technologies

This book brings together contributions from experts in the fields to describe the current status of important topics in solid-state circuit technologies. It consists of 20 chapters which are grouped under the following categories: general information, circuits and devices, materials, and characterization techniques. These chapters have been written by renowned experts in the respective fields making this book valuable to the integrated circuits and materials science communities. It is intended for a diverse readership including electrical engineers and material scientists in the industry and academic institutions. Readers will be able to familiarize themselves with the latest technologies in the various fields

Emerging semiconductor nanostructure materials for single-photon avalanche diodes

Detecting of light at the single photon level has a far-reaching impact that enables a broad range of applications. In sensing, advances in single-photon detection enable low light applications such as night-time operation, rapid satellite communication, and long-range three-dimensional imaging. In biomedical engineering, advancing single-photon detection technologies positively impacts patient care through important applications like singlet oxygen detection for dose monitoring in cancer treatment. In industry, impacts are made on state-of-the-art technologies like quantum communication which relies on the efficient detection of light at the fundamental limit. While the high impact of single-photon detection technologies is clear, the potential for improvement and challenges faced by prominent single-photon detection technologies remains. Superconducting single-photon detectors push the bounds of performance, but their high cost and lack of portability limits their prospect for far reaching applicability. Single-photon avalanche diodes (SPADs) are a promising alternative which can be made portable, absent of the need for cryogenic cooling, but they generally lack the performance of superconducting detectors. The materials in SPAD designs dictate operation, and conventional materials implemented being defined according to intrinsic material properties, limits SPAD performance. However, new classes of advanced materials are being realized which exhibit modified electromagnetic properties from the engineered arrangement of subwavelength structural units and low-dimensional properties. Such materials include metamaterials and low-dimensional materials, and they have been shown to enhance optoelectrical properties that are critical to avalanche photodiodes, like rapid photo response, enhanced absorption, and reduced dark current. In this work, the application of such advanced materials in SPADs is explored. Tapered nanowires and nanowire arrays are optimized for enhanced absorption and shown experimentally at room temperature to demonstrate high speed near-unity absorptance response at the single-photon level. In the metamaterial and nanowire devices, the gain and timing jitter are shown to be significantly improved over conventional bulk-based designs. Furthermore, the modelling of metamaterials in a SPAD device design and its operation with external single-photon detection circuitry is studied. The analysis is further shown to extend down to single nanowire devices which offers an elegant approach for integrated photonic circuits

Thermomechanical issues of high power laser diode catastrophic optical damage

Catastrophic optical damage (COD) of high power laser diodes is a crucial factor limiting ultra high power lasers. The understanding of the COD process is essential to improve the endurance of the high power laser diodes. COD is observed as a process in which the active part of the laser diode is destroyed, forming characteristic defects, the so called dark line defects (DLDs). The DLDs are formed by arrays of dislocations generated during the laser operation. Local heating associated with non-radiative recombination is assumed to be at the origin of the COD process. A summary of the methods used to assess the COD, both in real time and post-mortem is presented. The main approaches developed in recent years to model the heat transport in the laser structures under non homogeneous temperature distribution are overviewed. Special emphasis is paid to the impact of the low dimensionality of QWs in two physical properties playing a major role in the COD process, namely, thermal conductivity and mechanical strength. A discussion about the impact of the nanoscale in both physical properties is presented. Finally, we summarize the main issues of the thermomechanical modelling of COD. Within this model the COD is launched when the local thermal stresses generated around the heat source overcome the yield stress of the active zone of the laser. The thermal runaway is related to the sharp decrease of the thermal conductivity once the onset of plasticity has been reached in the active zone of the laser.Junta de Castilla y León (Projects VA081U16 and VA283P18)Spanish Government (ENE 2014-56069-C4-4-R, ENE 2017-89561-C4-3-R, FPU programme 14/00916)

Performance characterization of a millimeter-wave photomixer

xvii, 120 leaves : ill. (chiefly col.) ; 29 cmOur group purchased a THz photomixer from the Millimeter Wave Technology Group at the Rutherford Appleton Laboratory in London, UK. A photomixer is based on optical heterodyne conversion where a photoconductor or photodiode is illuminated by two laser beams with a difference frequency in the THz region. The beat frequency of the two lasers will modulate the conductivity of the photomixer material. The variation of the conductivity is converted to electrical current and finally radiation by applying a bias voltage across the active region of the device. My thesis concerns the determination of the characteristics of the photomixer, which is an expensive and extremely sensitive piece of equipment, to optimize its performance in support of a number of research activities within the group

Élaboration de photoconducteurs d’InGaAsP par implantation d'ions de fer pour des applications en imagerie proche-infrarouge et spectroscopie térahertz

Cette thèse décrit l’incorporation de fer dans l’hétérostructure InGaAsP/InP par implantation ionique à haute énergie (MeV) suivi d’un recuit thermique rapide. L’alliage quaternaire InGaAsP est tout indiqué pour fabriquer des couches photoconductrices qui peuvent absorber dans le proche-infrarouge, à 1.3 µm ou 1.55 µm. Ce procédé vise à développer de nouveaux matériaux de forte résistivité pour l’holographie photoréfractive et la spectroscopie térahertz pulsée. À notre connaissance, cette investigation représente les premiers essais détaillés de l’implantation de fer dans le matériau InGaAsP/InP. Les principaux paramètres de fabrication, tels la fluence d’ions de fer, la température d’implantation et la température de recuit ont été explorés. Les propriétés physiques des matériaux produits ont été étudiées avec des mesures électriques (résistivité et effet Hall avec l’analyse de Van der Pauw), optiques (photoluminescence, absorption et réflectivité différentielle résolue en temps) et structurales (diffraction de rayons X, canalisation de la rétrodiffusion Rutherford et microscopie électronique en transmission). Pour fabriquer des couches à forte résistivité pour des applications holographiques à 1.3 µm, nos résultats ont montré qu’il est préférable d’éviter l’amorce de l’amorphisation lors de l’implantation du quaternaire pour maintenir une bonne qualité cristalline après recuit. Ceci favoriserait une compensation par l’activation du fer comme impureté profonde. Une résistivité de l’ordre de 10[indice supérieur 4] Ωcm est mesurée après recuit. Pour fabriquer des couches à forte résistivité pour des applications de spectroscopie térahertz pulsée à 1.55 µm, nous privilégions l’amorphisation par implantation froide et la recristallisation, ce qui réduit le temps de recombinaison des photoporteurs sous la picoseconde. L’émission d’ondes térahertz par ce matériau est démontrée sur une largeur de bande de 2 THz. L’évidence expérimentale montre la formation d’une microstructure polycrystalline dans la couche d’InGaAsP, ayant une forte densité de fautes planaires et une taille de grains nanométrique qui varient avec la température de recuit, ce qui suggère une connexion avec les propriétés optoélectroniques du matériau