Fluids are used for intravenous infusion during practically all surgeries, but several different compositions are available on the market. Crystalloid fluids comprise lactated or acetated Ringer solutions, normal saline, Plasma-Lyte, hypertonic saline, and glucose. They lack allergic properties but are prone to cause peripheral tissue oedema. Their turn­ over is governed by physiological factors such as dehydration and drug effects. Colloid fluids include hydroxyethyl starch, albumin, dextran, and gelatin. These fluids have various degrees of allergic properties and do not promote peripheral oedema. Their half-life is usually about hours. Factors increasing the turnover rate are poorly known but might include inflammatory states. Current debates include the widespread use of normal saline, which should be replaced by Ringer’s or Plasma-Lyte in most situations, and the kidney damage associated with the use of starch in septic patients. New studies show that hypertonic saline does not improve survival or neurological damage in prehospital care.

Current-voltage (I-V) characteristics of organic molecular glasses and solution processable materials embedded between two electrodes were studied to find materials possessing high charge-carrier mobilities and to design organic memory devices. The comparison studies between TOF, FET and SCLC measurements confirm the validity of using analyses of I-V characteristics to determine the mobility of organic semiconductors. Hexaazatrinaphthylene derivatives tri-substituted by electron withdrawing groups were characterized as potential electron transporting molecular glasses. The presence of two isomers has important implications for film morphology and effective mobility. The statistical isomer mixture of hexaazatrinaphthylene derivatized with pentafluoro-phenylmethyl ester is able to form amorphous films, and electron mobilities with the range of 10 E cm2/Vs are observed in their I-V characteristics. Single-layer organic memory devices consisting of a polymer layer embedded between an Al electrode and ITO modified with Ag nanodots (Ag-NDs) prepared by a solution-based surface assembly demonstrated a potential capability as nonvolatile organic memory device with high ON/OFF switching ratios of 104. This level of performance could be achieved by modifying the ITO electrodes with some Ag-NDs that act as trapping sites, reducing the current in the OFF state. Based upon the observed electrical characteristics, the currents of the low-resistance state can be attributed to a tunneling through low-resistance pathways of metal particles originating from the metal top electrode in the organic layer and that the high-resistance state is controlled by charge trapping by the metal particles including Ag-NDs. In an alternative approach, complex films of AgNO3: hexaazatrinaphthylene derivatives were studied as the active layers for all-solution processed and air-stable organic memory devices. Rewritable memory effects were observed in the devices comprised of a thin polymer dielectric layer deposited on the bottom electrode, the complex film, and a conducting polymer film as the top electrode. The electrical characteristics indicate that the accumulation of Ag+ ions at the interface of the complex film and the top electrode may contribute to the switching effect.

In this paper, we use a room temperature processing system, Liquid Phase Deposition(LPD) method, to grow silicon dioxide. The advantages are cheap equipment, low temperature growth, and no thermal stress. The quality is good enough to be used in IC devices. To inverstigate the properties of silicon Dioxide, we have done different physical and chemical test, including AES,TEM,FTIR,P-etch rate. We used the high frequency C-V curve to study the interface properties. The leakage current help to clarify the film quality. Moreover, we also discuss the growth mechanism in order to more understanding of LPD method.

This work has employed the Micro-wave Plasma enhanced Chemical Vapor Deposition (MPCVD) method to fabricate diamond PN junction device. The n+ <111> orientation single-crystal silicon has used as substrates. P-type diamond layer is doped with B(OCH3)3 and the N-type diamond layer is doped with ammonia. The surface structure of diamond film has been observed by scanning electron microscope; and the device rectification property of a PN junction has measured by current-voltage characteristic. The carrier density and mobility of diamond films have been analyzed by Hall measurement. Furthermore, the Cathodoluminescence (CL) spectroscopy showed the defect spectra in diamond PN junction. The N-type diamond film and P-type diamond film have deposited at temperature of 800 ¢J, for 30 minutes and 90 minutes, respectively. The process CVD has performed in the same chamber continually. A I-V curve of sample showed the set on positive voltage 0.5 V and the reverse breakdown voltage of 6 V. Further, CL results revealed a peak at 285 nm (4.4 eV), which represents the CVD diamond band and the other one is at 500 nm (2.5 eV), which stands for donor-acceptor recombination from defect in these diamond films.

A film which is optically transparent and electrically conductive is difficult to come by but can be realized in ways such as doping an oxidized film or by oxidizing a metallic film resulting in what is known as a transparent conducting oxide (TCO). TCO's have many important uses in electronics, especially as the top contact in to solar cells where efficient transmission of light and low electrical resistivity allow for higher efficiency solar cells and as the gate contact in AlGaN/GaN HFET's allowing for optical characterization of the subsurface transistor properties. Because these devices rely heavily on the characteristics of its material interfaces, a detailed analysis should be done to investigate the electrical effects of implementing a TCO. In this work, the electrical characterization of ruthenium dioxide (RuO₂) Schottky contacts to gallium nitride (GaN) formed by evaporating ruthenium with a subsequent open-air annealing is presented. The results gathered from the current-voltage-temperature and the capacitance-voltage relationships were compared to ruthenium (Ru) on GaN and platinum (Pt) on GaN. Additionally, the measurement and analysis procedure was qualified on a similar structure of nickel on GaAs due to its well-behave nature and presence in the literature. The results indicate that an inhomogeneous Gaussian distribution of barrier heights exists at the RuO₂/GaN interface with an increase of 83meV in the mean barrier height when compared to Ru/GaN. / Master of Science

Le carbure de silicium (SiC) semble être actuellement le candidat le plus viable des semi-conducteurs à large bande interdite pour remplacer le silicium (Si) dans un avenir proche. En raison de ses propriétés intrinsèques, le SiC permet de développer des dispositifs à semi-conducteurs aux caractéristiques supérieures offrant de grandes améliorations de performances, et se traduisant également par des conceptions plus efficaces et compactes dans diverses applications de l'électronique de puissance. Les MOSFET de 1,2 kV SiC, de loin les composants les plus répandus de la famille pour équiper les sources de puissance, ont rapidement été déployés pour remplacer les modules IGBT Si en raison de leur résistance à l'état passant faible et de leurs excellentes performances de commutation dans toutes les plages de température. Cependant, encore à un stade précoce de développement, les MOSFET SiC présentent leurs problèmes techniques et économiques propres, lesquels problèmes ont freiné leur expansion en électronique de puissance. La caractérisation et la modélisation, en particulier l'état de fonctionnement du MOSFET SiC, ont été examinées dans le cadre de cette thèse afin de mettre en lumière les spécificités et les conséquences qui en découlent sur la conception des convertisseurs de puissance. C’est ainsi qu’une méthodologie de caractérisation statique pour les MOSFET à haute tension a été développée. Les caractéristiques ont été mesurées par méthodes appropriées permettant à la température de la jonction de rester constante pendant la mesure. Les résultats expérimentaux ont été analysés et comparés à ceux relatifs aux dispositifs conventionnels en Si. Ensuite, un nouveau modèle compact du module MOSFET SiC a été mis au point sur le logiciel Saber pour des simulations orientées circuit. Ce modèle prend en compte les phénomènes physiques observés, notamment les effets des pièges d’interface, le comportement JFET intrinsèque, le canal court et la température. En tant que version modifiée de Shichman Hodges, le modèle utilise un nombre raisonnable de paramètres d’ajustement, lesquels sont principalement extraits par identification des courbes de données expérimentales à l’aide d’un logiciel d’optimisation, et pour les autres étant basés sur les données disponibles dans la fiche technique du composant étudié. Finalement, nous avons abordé la caractérisation électro-thermique des MOSFET de SiC. Pour remédier à la présence de pièges d'interface, des bancs de test dédiés ont été développés pour la mesure de la température MOSFET au SiC sur la base du TSEP. Une simulation par éléments finis 3D (FEM) est réalisée pour étudier la distribution thermique à l'intérieur du module. En comparant avec les expériences, le modèle électro-thermique a été validé avec une précision acceptable. / Silicon carbide (SiC) has actively been emerged as the most viable candidate of the wide band gap (WBG) semiconductors to replace silicon (Si) in the near future. Due to its inherent properties, SiC enables the development of new generation semiconductor devices that offer great performance improvements, resulting in more efficient and compact designs in various power electronics applications. The 1.2 kV SiC MOSFETs, which are by far the most important devices in the SiC family, have been quickly used as the replacement of Si IGBTs in many applications due to their superior characteristics. However, at an early stage of development, SiC MOSFETs come with their own list of technical and economic issues which have somehow limited their widespread implementation for power electronics applications. The characterization and modeling, in particular on-state of the SiC MOSFET, have been investigated in this dissertation to develop insight of the unique characteristics along with the effects on the design of power converters. In such a way, the characterization test benches for high voltage power MOSFETs have been developed. The device is characterized using appropriate methods, which allows the junction temperature to remain constant during the measurement. The characteristics are then analyzed and compared to these of Si counterpart to provide further understanding of SiC MOSFETs. Subsequently, a novel compact model has been developed for circuit simulation, taking into account physical phenomena including interface traps, short-channel, intrinsic JFET and temperature effects. As a modified version of the Shichman Hodges, the model employs a few adjustment parameters, which are mostly derived from curve fitting of experimental data, using optimization tool software. The proposed model with fairly simple current equation thus is expedient to represent the DC behavior of power MOSFET for a wide range of operation conditions. In the end, the thermal characterization of SiC MOSFETs is examined. The on-resistance has been proposed as a temperature-sensitive electrical parameter (TSEP) to estimate the junction temperature. In the presence of the interface traps, the dedicated test benches have been developed for SiC MOSFET temperature measurement based on TSEP. 3D Finite element (FEM) simulation is performed to investigate thermal distribution inside the module. By comparing with the experiments, the electro-thermal model is validated with acceptable accuracy.

Židininiai kepenų pakitimai (ŽKP) – vieni dažnesnių patologinių radinių tiriant pacientus dėl įvairių virškinimo ar kitų organizmo sistemų ligų. Įvairių spindulinės diagnostikos metodų dėka nustačius patologinius židinius kepenyse ypač svarbi jų klinikinė diferencinės diagnostikos reikšmė. ŽKP diferencinės diagnostikos esmė yra kiek įmanoma tikslesnis židinio kepenyse kraujotakos nustatymas ir aprašymas. Šios problemos sprendime naujų galimybių įgyja santykinai nauja ir Lietuvoje niekur kitur dar neatliekama UG tyrimo su i/v kontrastavimu metodika, kurios metu gaunami rezultatai lyginami su dominuojančių įprastų KT ir MRT kontrastinių tyrimų rezultatais. Tikslas: nustatyti radiologinių tyrimų vertę diagnozuojant židininius kepenų pakitimus (ŽKP) Uždaviniai: 1. Nustatyti įprastinio UG, UG su i/v kontrastavimu ir KT su i/v kontrastavimu diagnostikos metodų tikslumo rodiklius nepiktybiniams ir piktybiniams ŽKP. 2. Nustatyti UG ir KT su i/v kontrastavimu vertingiausius diagnostikos kriterijus vertinant židininių kepenų pokyčių prigimtį. 3. Palyginti tarpusavyje UG ir KT su i/v kontrastavimu nustatytų židininių kepenų pakitimų diagnostikos metodų tikslumo rodiklius nepiktybiniams ir piktybiniams ŽKP. 4. Įvertinti kepenų hemangiomų radiologinių diagnostikos metodų tikslumo vertę. / Focal hepatic lesions (FHL) are one of the most common pathological findings in patients who are examined for gastrointestinal or other diseases. The rigorous description of blood circulation in the hepatic focus is essential in differential diagnosis of FHL. US with i/v contrast enhancement is a new imaging method enabling definition of nature of FHL, follow-up, treatment efficacy and monitoring for possible relapse of the process. This study is conducted solely in the Radiology Department of Kaunas University of Medicine Hospital. Aim of the study To evaluate and compare the value of ‘bolus’ contrast-enhanced CT and contrast-enhanced US in diagnostics of focal hepatic lesions. Tasks of the study 1. To determine rates of diagnostic accuracy of conventional US, US with i/v contrast enhancement and ‘bolus’ contrast-enhanced CT in diagnosis of benign and malingnant FHL. 2. To establish the main and most effective diagnostic criteria of US and CT with i/v contrast enhancement for the assessment of nature of focal hepatic lesions. 3. To compare rates of diagnostic accuracy of US with i/v contrast enhancement and ‘bolus’ contrast-enhanced CT in diagnosis of benign and malingnant FHL. 4. To assess the reliability of radiological diagnostics of hemangioma, comparing the results of US, CT, and MRI.

Le travail de la thèse proposé consiste à étudier, caractériser et modéliser la performance et la fiabilité de composants semi-conducteurs sous conditions extrêmes c’est à dire pendant et après que ces composants ont subi un stress électrique, un stress thermique voire les deux stress en même temps. Les composants semi-conducteurs que nous avons étudiés sont des modules photovoltaïques en silicium monocristallin pour des applications dans les énergies renouvelables. Dans cette étude, ces composants ont été soumis à plusieurs types de dégradations générant des défauts localisés dans la structure des composants. Dans un premier temps, des études approfondies des caractéristiques I(V) et C(V) et des paramètres électriques des modules solaires photovoltaïques ont été réalisées en testant une série de modules sous différentes conditions environnementales afin de fournir des données pertinentes pouvant être utiles pour l'évaluation des performances, la modélisation du fonctionnement et pour la mise en œuvre correcte et complète des modules photovoltaïques. Ces caractérisations ont été complétées par l’étude des défauts créés à l’interface et dans les structures des modules photovoltaïques par les différents stress sur la base de mesures effectuées sur ces mêmes cellules par la technique Deep Level Transient Spectroscopy (DLTS). Grâce à cette technique, nous avons identifié et localisé ces défauts au sein du composant, en déterminant leur énergie d’activation et leur section efficace de capture. Les résultats de notre étude montrent ainsi l’importance des conditions de fonctionnement sur les performances instantanées et sur le long terme des systèmes photovoltaïques. Ils peuvent être exploitables directement dans la conception même des modules silicium voire transposable, en suivant la méthodologie de l’étude que nous proposons à de nouvelles technologies de modules / The objective of this work aim to study the performance, reliability of semiconductor structures after their operation under extreme conditions, during and after electrical stress, thermal stress, and combined electro thermal stresses. The studied semiconductor structures are photovoltaic cells for applications in the field of renewable energies. These devices have been exposed to several types of degradation generating localized defects in the structures. The I (V) and C (V) characteristics and electrical parameters have been studied before and after each stress case. The Deep Level Transient Spectroscopy (DLTS) was used as advanced technique for tracking the defects created at the interface and in the bulk structures. The DLTS technique allows identifying and locating these defects within the devices, by determining their activation energy and their capture cross-Section

During recent years the thickness of the gate oxide has been reduced considerably. The progressive miniaturization of devices has caused several phenomena to emerge such as quasi-breakdown, direct tunneling and stress induced leakage currents. Such phenomena significantly modify the performance of the scaled-down MOSFETs. As a part of this research work, an effort has been made to study the performance and characteristics of the thin Gate oxide for MOSFETs and Tunnel Oxide for Floating Gate (FG) MOS devices. The exponential dependence of tunnel current on the oxide-electric field causes some critical problems in process control. A very good process control is therefore required. This can be achieved by finding out the exact value of F-N tunneling parameter. This research work also is an effort of finding an accurate value for parameter B and its dependence on the oxide thickness as the device are scaled down to a level where the probability of Direct Tunneling mechanism gains more prominence. A fully automated Low Current Measurement workstation with noise tolerance as low as 10-15 A was set up as a part of this research. C-V and I-V curves were analyzed to extract, determine and investigate the oxide thickness dependence of F-N parameter B. For oxide thickness in the range10~13 nm, the parameter B ranged between 260 and 267. Thus it can be said that it is not sensitive to the change in oxide thickness in this range. However it was noticed that for thickness around 7nm wide variety of results were obtained for the Fowler-Nordheim parameter B (B ranged from 260 to 454). This can be attributed to the enhancement in the leakage current due to the direct tunneling. Hence to have tight control over VT for a NVM, new algorithms need to be developed for even better process control for oxide thickness in the range of 7 nm and below.

A Metal-Insulator-Metal (MIM) diode is a high frequency device used for energy harvesting purpose in the RECTENNA. The main objective of this thesis work is to design, fabricate and characterize a thin-film MIM diode. A key issue associated in this research work is the development MIM diode with nanometer thin insulator region. The reason for the development of MIM diode is to rectify a wide spectrum of AC signal to usable DC power. In this thesis work, a planar MIM diode with Aluminum/Aluminum-Oxide/Gold has been fabricated. The thickness of the insulator region obtained was about 3nm. The Metal and insulator depositions were done by sputtering and plasma oxidation, respectively. I-V Characteristics of the diode was measured by making use of in-house set-up and 70% of the devices on a single wafer yielded with better result. Most of the I-V curves obtained were highly non-linear and asymmetric. Based on the I-V measurement, the logarithmic derivative of I vs. V was plotted and the tunneling behavior was also observed.