Simulation and analysis of the forward bias current–voltage–temperature characteristics of W/4H-SiC Schottky barrier diodes for temperature-sensing applications

Abstract The current-voltage (ID-VD) characteristics of W/4H-SiC Schottky barrier diodes (SBDs) are investigated in the 303–448 K temperature range by means of a numerical simulation study. Results showed a good agreement with measurements for a bias current ranging from 100 nA up to 10 mA. The main device parameters, such as the barrier height and ideality factor are found strongly temperature-dependent. The observed behaviours are interpreted by using the thermionic emission (TE) theory with a single Gaussian distribution of the barrier height (BH). The corresponding Richardson constant is A* = 148.8 Acm−2K−2. This value is close to the theoretical one of 146 Acm−2K−2 for n-type 4H-SiC

La résistivité d'une diode au silicium utilisée comme détecteur de particules

La résistivité (ρ) d’une structure p+nn+ au silicium, utilisée comme détecteur de particules travaillant dans un environnement hostile et soumis à de fortes fluences, est simulé numériquement en utilisant la méthode des différences finies. Lorsque cette jonction est soumise à des fortes radiations, des défauts structuraux sont créés qui ont des effets indésirables et peuvent dégrader les performances des détecteurs. Ces défauts se manifestent comme des pièges accepteurs et des centres de génération-recombinaison (g-r).La résistivité augmente avec l’augmentation de la densité du piège accepteur pour atteindre la résistivité intrinsèque (maximale)

Modeling of Charge Transfer Inefficiency in a CCD with High Speed Column Parallel Readout

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex detector of a future Linear Collider. The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. An Analytic Model has been developed for the determination of the charge transfer inefficiency (CTI) of a CPCCD. The CTI values determined with the Analytic Model agree largely with those from a full TCAD simulation. The Analytic Model allows efficient study of the variation of the CTI on parameters like readout frequency, operating temperature and occupancy.Comment: 5 pages, 13 figures, presented on behalf of the LCFI Collaboration, proceedings IEEE 2008 Nuclear Science Symposium, Dresden, Germany, and 11th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD08) 2008, Siena, Ital

MÉCANISME DE BRANCHEMENT ET PRÉCIPITATION LAMELLAIRE DANS L’ALLIAGE CU-7, 5 ÀT. % IN BRANCHING MECHANISM AND LAMELLAR PRECIPITATION IN THE CU-7, 5 AT. % IN ALLOY

L'intérêt de ce travail est la mise en évidence d'une part de l’effet de la déformation plastique sur les mécanismes gouvernant la précipitation discontinue et d’autre part la morphologie du précipité lamellaire dans l’alliage Cu-7,5 at.% In. Différentes techniques d'analyses ont été utilisées à cet égard tels que: la microscopie optique, l'analyse thermique différentielle et la microscopie électronique à transmission (MET). Les résultats obtenus lors du vieillissement de l'alliage Cu-7,5 at.% In à 400 °C, sont cohérents entre eux et confirment plusieurs travaux consacrés à ce domaine, tels que le développement des précipités lamellaires à partir d’un joint de grain, différentes orientations des lamelles dans la même cellule ont été aussi observées. La réaction discontinue peut se développer aussi dans les joints de d’interphases et dont le mode favorable de multiplication des lamelles est le mécanisme de branchement. The aim of this work is to make the evidence on the one hand the effect of the plastic deformation on the mechanism of the discontinuous precipitation and the lamellar precipitate morphology in the Cu-7, 5 at. % In alloy. Different techniques of analysis have been used in this respect such as the optical microscopy, the differential thermal analysis and electron and transmission microscopy.The obtained results during aging of the alloy Cu-7, at 5% In at 400 ° C confirm various works achieved in this field it was observed that the lamellar precipitates develop starting from a grain boundary and deferent lamellar orientations in the same cell were observed. The discontinuous reaction can also develop in the interphase boundaries and the branching mechanism is the favourable mode of the precipitate lamellas multiplication

DURCISSEMENT STRUCTURAL DE L’ALLIAGE AL-6.2%ZN-2.5%MG-1.7% CU SOUS L’EFFET DES TRAITEMENTS THERMOMECANQUES HARDENING STRUCTURAL OF ALLOY Al-6.2%Zn-2.5%Mg-1.7% Cu UNDER THE INFLUENCE OF PROCESSING THERMOMECANQUES

Le but de ce  travail est  la mise en évidence de  l'effet des  traitements  thermomécaniques  sur    les propriétés de  l'alliage Al-6.2%Zn-2.5%Mg-1.7% Cu par  les  techniques d'analyses  thermique et de calorimétrie  (DSC), qui sont des méthodes d'essai largement utilisées pour des finalités de recherche et de contrôle de qualité. Les effets des traitements thermomécaniques sur les  deux  grandeurs  à  savoir  le  coefficient  de  dilatation  thermique  et  la  capacité  calorifique,  peuvent  nous  donner  des informations  complémentaires  pour  une  meilleure  compréhension  des  phénomènes  responsables  du  comportement thermodynamique  de  l’alliage.  Les  résultats  obtenus  ont  montré  d'une  part,  qu'il  existe  une  grande  similitude  entre  le coefficient linéaire de dilation thermique et la capacité calorifique et d'autre part l’effet de la déformation plastique notable est mis en évidence par les changements de l’allure des courbes par rapport à l'état brut. De même la cinétique de la précipitation de  la  phases η’  est  accélérée  dans  le  cas  des  échantillons  homogénéisé  et  homogénéisé +  déformé et accompagnée par un décalage du domaine des  températures   vers des  températures plus basses que celles enregistrées dans  le cas du matériau à l’état brut. The  aim  of  this work  is  the  demonstration  of  the effect of  thermomechanical  treatments on  the properties of  the alloy Al-6.2%Zn-2.5%Mg-1.7% Cu by thermal analysis techniques and calorimetry, which are methods of test widely used for research purposes  and  quality  control.  The  effects  of  thermomechanical  treatments  on  the  two  variables  namely  the  coefficient  of thermal  expansion  and  heat  capacity,  we  can  provide  further  information  for  better  understanding  of  the  phenomena responsible for the thermodynamic behavior of the alloy. The results showed the one hand, there is great similarity between the linear  coefficient  of  thermal  expansion  and  heat  capacity,  and  secondly  the  effect  of  plastic  deformation  is  evidenced  by changes in the shape of the curves from the rough. Similarly the kinetics of precipitation of η phase is accelerated in the case of samples homogenized and homogenized + distorted and accompanied by a shift in the temperature range to lower temperatures than those recorded in the case of the material state Gross

Study and Assessment of Defect and Trap Effects on the Current Capabilities of a 4H-SiC-Based Power MOSFET

A numerical simulation study accounting for trap and defect effects on the current-voltage characteristics of a 4H-SiC-based power metal-oxide-semiconductor field effect transistor (MOSFET) is performed in a wide range of temperatures and bias conditions. In particular, the most penalizing native defects in the starting substrate (i.e., EH6/7 and Z1/2) as well as the fixed oxide trap concentration and the density of states (DoS) at the 4H-SiC/SiO2 interface are carefully taken into account. The temperature-dependent physics of the interface traps are considered in detail. Scattering phenomena related to the joint contribution of defects and traps shift the MOSFET threshold voltage, reduce the channel mobility, and penalize the device current capabilities. However, while the MOSFET on-state resistance (RON) tends to increase with scattering centers, the sensitivity of the drain current to the temperature decreases especially when the device is operating at a high gate voltage (VGS). Assuming the temperature ranges from 300 K to 573 K, RON is about 2.5 MΩ·µm2 for VGS > 16 V with a percentage variation ΔRON lower than 20%. The device is rated to perform a blocking voltage of 650 V

Simulations of the Temperature Dependence of the Charge Transfer Inefficiency in a High-Speed CCD.

Results of detailed simulations of the charge transfer inefficiency of a prototype serial readout CCD chip are reported. The effect of radiation damage on the chip operating in a particle detector at high frequency at a future accelerator is studied, specifically the creation of two electron trap levels, 0.17 eV and 0.44 eV below the bottom of the conduction band. Good agreement is found between simulations using the ISE-TCAD DESSIS program and an analytical model for the former level but not for the latter. Optimum operation is predicted to be at about 250 K where the effects of the traps is minimal; this being approximately independent of readout frequency in the range 7-50 MHz. This work has been carried out within the Linear Collider Flavour Identification (LCFI) collaboration in the context of the International Linear Collider (ILC) project

Radiation hardness studies in a CCD with high-speed column parallel readout

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying shortlived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex detector of the International Linear Collider (ILC). The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. The results of detailed simulations of the charge transfer inefficiency (CTI) of a prototype CPCCD are reported and studies of the influence of gate voltage on the CTI described. The effects of bulk radiation damage on the CTI of a CPCCD are studied by simulating the effects of two electron trap levels, 0.17 and 0.44 eV, at different concentrations and operating temperatures. The dependence of the CTI on different occupancy levels (percentage of hit pixels) and readout frequencies is also studied. The optimal operating temperature for the CPCCD, where the effects of the charge trapping are at a minimum, is found to be about 230 K for the range of readout speeds proposed for the ILC. The results of the full simulation have been compared with a simple analytic model