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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The non-linear electric resistivity of Au thin film on silicon after rapid thermal annealing

Wang, wei-chi 25 June 2002 (has links)
ABSTRACT In this work , a Four-Point probe electrical measurement system has been set up to investigate the non-linear conductivity of gold thin film on silicon . The annealing effect of gold thin films has been carried out by a rapid thermal annealing system using a modified tube furnace .The conductivities of gold thin film on silicon are studied for film thickness of 100-500 Å , different annealing temperature from 150-500¢J, annealing duration of 10-40mins on two kinds of substrate¡]n-type¡Bp-type silicon¡^. Samples are examined by SEM¡BAFM¡BXRD and FTIR to characterize the surface morphology of gold thin film on silicon , the silicide formation,and non-linear dc response in every different conditions. Finally , we proposed a Random Tunneling Junction Network model to explain the non-linear dc response and discussed the correlation between the tunneling junction of gold clusters and the changes of it¡¦s distribution , the silicide formation combining with breakdown of the junction bridges and the parameters from the RTJN model. Our numerical result reveals good agreement with the experiment data.
2

Fabrication of crystalline SiGe thin film on silicon wafer by rapid thermal annealing process

Lin, Ya-Shu 15 July 2004 (has links)
In order to improve the stability of interface between the solar cell (CuInSe2) and the substrate, such as reducing the lattice misfit and the number of defects at the interface, we used the Solid Phase Epitaxy (SPE) method to grow epitaxial germanium film as the substrate of solar cell. The experiment tried three different film structures. The first structure was sequential sputtering an amorphous silicon film and a germanium film on the silicon wafer. The next one was sputtering an amorphous germanium film on the bare silicon wafer. The last, called mixed step structure, was co-sputtering the amorphous silicon and germanium films by changing the sputtering power and time. After the recrystallization of amorphous films by rapid thermal process, x-ray diffraction patterns were performed to characterize the crystallinity of the processed films. The experimental results appeared that the epitaxy of amorphous films was not successful and that there was only polycrystalline films formed. TEM images of the processed amorphous films showed that there existed a thin native oxide layer at the interface between the silicon substrate and the polycrystalline films. The thin oxide layer (less than 10 nm) caused the epitaxy of amorphous films not to proceed.
3

A study of rapid thermal selenization process of CuInSe2 films

Pan, Chia-jui 11 July 2009 (has links)
By evaporating single element to grow two kinds of stacked layer precursors In/Cu/Se and In/Se/Cu first, In/Cu/Se precursor forms as CuSe2, CuSe and In metal phase, but In/Se/Cu precursor forms mainly as Cu11In9 alloy, In metal phase and amorphous Se. In RTA selenization process, the two kinds of stacked layer precursors form to CuInSe2 (for short as CIS) thin film in different reaction mechanisms, but both of the two stacked layers form to CIS with rough surface and uncompact structure, not the ideal thin film. Replacing by co-evaporating two elements to grow two kinds of binary stacked layrer precursors InSe/CuSe/Se and InSe/Cu/InSe/Se, finds that, after the RTA selenization process, both of the two precursors form CIS with good smoothness and compactness, and InSe/CuSe/Se precursor with much better structure than the other, having mean grain size in about 1~3£gm. In this result, appears that if skipping the stage which single element reacts with Se, generating the selenide InxSey, CuxSey (Such as InSe, In2Se3, CuSe, Cu2Se et cetera.), and using In-Se, Cu-Se binary stacked precursors in RTA process directly can acquire better CIS structure. And then, growing InSe/CuSe/Se stacked layer on Mo metal back contact, finds the phenomenon that the formed CIS thin film has many circle bulges structure on Mo thin film. After investigating this case, the reason was considered as the remaining compressive stress of Mo thin film (-272.9MPa). The interface problem of Mo/CIS has been solved by tuning the remaining stress of Mo with 1£gm thickness to compressive stress -194MPa, and 1£gm thickness CIS thin film is grown on that. However, if the remaining stress continuingly drecrese to almost no stress 1MPa or tensile stress 709.9MPa, CIS thin film peels with Mo thin film from the substrate. In the end, analyzing the CIS thin film formed by InSe/CuSe/Se stacked layer precursor (Cu/In ratio is 24%/26%), the result shows that the CIS film is a P-type In-rich thin film, the sheet resistence is 6.8*106£[/ ¡¼, carrier mobility is 1.103*102 cm2/V-s, carrier density is 1.318*1018 cm-3, and energy gap is about 1.0eV, the absorption coefficient is above 6.5*104cm-1, and the composition all over the film is very close to each other¡Aappearing this film with nice composition homogenization.
4

The Study of LiTaO3 Pyroelectric Thin Film IR Detectors Prepared by a Sol-Gel Method and Rapid Thermal Annealing Technology

Li, Yi-Ju 16 July 2002 (has links)
The lithium tantalite [LiTaO3,abbreviated to LT] thin films were deposited on Pt/SiO2/Si substrates by spin coating with sol-gel processing and rapid thermal processing in this thesis. 1,3 propanediol was used as solvent to minimize the number of cycles of spin coating and drying processes to obtain the desired thickness of thin film. By changing the heating rate (600~3000¢J/min) and the heating temperature (500~800¢J), the effects of various processing parameters on the thin films growth are studied. The effects of various heating rate on the response of pyroelectric IR detector devices are studied also. Experimental results reveal that the heating rate will influence strongly on grain size, dielectricity, ferroelectricity and pyroelectricity of LT thin films. With the increase of heating rate, the grain size of LT thin film decreases slightly, and the C-axis orientation is enhanced. The relative dielectric constant of LT thin film increases from 28 up to 45.6, the tand increases from 0.033 to 0.134, Ec increases from 122 KV/cm to 183 KV/cm, Pr increases from 7.45 mC/cm2 to 12.12 mC/cm2, and g increases from 9.33´10-9 C/cm2K up to 2.66´10-8 C/cm2K, respectively, as the heating rate increases form 600 up to 3000¢J/min. In addition, the results also show that the LT thin film possesses the largest figures of merit Fv (2.19¡Ñ10-10 Ccm/J) and Fm (4.01¡Ñ10-9 Ccm/J) at the heating temperature of 700¢J and heating rate of 1800¢J/min. The voltage responsivities (Rv) measured at 80 Hz increase from 5496 to 8455 V/W and the specific detecivities (D*) measured at 300 Hz increase from 1.94¡Ñ108 to 2.38¡Ñ108 cmHz1/2/W with an increase of heating rate from 600 to 1800¢J/min. However, the voltage responsivity and the specific detecivity decrease with heating rate in excess of 1800¢J/min. The results show that LT1800 pyroelectric thin film detector exists both the maximums of voltage responsivity and specific detecivity. Therefore, LT1800 thin film exhibits the best IR characteristics for detector material.
5

Synthesis and optimization of a library of small molecule inhibitors of ricin toxin A

Pruet, Jeffrey Michael 13 November 2013 (has links)
Ricin is a potent cyctotoxin with no known antidote. Chapter 1 provides background and context for this thesis, which is primarily focused on probing the active site of Ricin toxin A (RTA). Relevant information about Ricin, its use, method of action, and noteworthy contributions towards the discovery of Ricin A chain inhibitors are provided. Furthermore, a brief description of the assays used by our collaborators to monitor RTA inhibition is provided. Additionally, a great deal of this thesis pertains to a particular heterocycle, pterin, and thus the remainder of Chapter 1 is dedicated to pterins, their physical properties, biological relevance, and selected reports of pterin chemistry. Chapter 2 details preliminary research focused on the use of nucleic acid-based platforms as RTA inhibitors. Two specific nucleic acids were chosen, adenine and guanine, and the chapter is split to address them individually. Rational for their use is provided, as well as the synthetic strategies investigated. Both platforms showed significant interference with the analysis assay, most pronounced for the adenine series. A primary goal throughout this thesis is the identification of a simple, rapid method to provide a library of new compounds. To this end, discussion of improved synthetic routes are provided within the section dedicated to guanines. Initial investigation into pterins as a platform for RTA inhibitors is provided in Chapter 3. Much of this chapter is concerned with hurtles encountered while dealing with the poor solubility of pterins, purification, and limits in reaction scope. Finally this chapter details a significant discovery in pterin's utility, both in terms of synthetic ease and preference towards one regioisomer over another. A variety of amides are initially used to probe the active site for significant interactions to the pterin pendents. Chapter 4 builds off the discoveries detailed within the previous chapter. Efforts to optimize the preliminary amide series from Chapter 3 are described, leading to a significant enhancement in activity. Additionally, Chapter 4 describes a synthetic breakthrough which greatly enhanced the speed of synthesis and complexity of the designed pterin inhibitors. Building upon the goal to map the RTA active site, a description of various peptide conjugated pterins is provided, as well as efforts to arrive at optimized isosteres of the most promising peptide derivatives. / text
6

An improvement in the selenization process of CuInSe2

Ho, Yu-yang 16 August 2010 (has links)
By using Al interlayer to separate Cu and In, but Al is very easy to be oxidized by air. For avoiding that, using In layer can achieve that goal. And using Al interlayer can reduce the roughness of the CIS surface. The other idea is to substitute Al by Sb. In RTA selenzation process, the roughness of the CIS surface by with Sb interlayer is much smoother than using Al interlayer. And the grain with Sb interlayer is more compact (mean grain size is more than 1£gm). The composition test of CIS is measured by EPMA and EDS of TEM. In EPMA measurement, the composition of CIS by using Sb interlayer is more uniform (standard deviation is less than 1 atomic percent), and the composition of CIS by using Al interlayer is less uniform (standard deviation is 1 to 2 atomic percent). In these experiments, the assumption of composition of CIS is Cu/In=1.05, CIS with Al interlayer is Cu/In=1.05, CIS with Sb interlayer is Cu/In=0.90, and the results are 1.05, 1.05, and 0.89. The assumption is very close to the result. In EDS of TEM measurement, the results are the same as the result of paper (composition is different everywhere) and the standard deviation are bigger than 1 atomic percent, but the mean composition is similar to EPMA.
7

The Characterization of Sn-doped SiO2 Thin Film Resistance Random Access Memory

Liao, Kuo-Hsiao 26 August 2011 (has links)
In this study, The bottom electrode¡]TiN¡^, middle insulator ¡]Sn¡GSiO2¡^, and top electrode ¡]Pt¡^ were deposited respectively by sputtering technique for fabricating the resistive random access memory with metal-insulator-metal structure. Experimental results were indicated that Sn-dopped SiO2 RRAM could be operated over 105 times and retention time was kept stable at thermal stress up to 85 ¢J over 104 s. In the previous researches, we had known that the supercritical carbon dioxide¡]SCCO2¡^ fluids could efficiently to passivate the traps in the devices. The leakage current of dielectric film would be reduced significantly after SCCO2 fluids treatment. To improve the dielectric properties of Sn-dopped SiO2 films, the SCCO2 fluids technology was introduced in this study. After SCCO2 fluids treatment, the leakage current of devices was reduced significantly, because the HRS conduction mechanism was transformed from Poole-Frenkel conduction to Schottky emission and the LRS conduction mechanism was transformed from Ohmic conduction to Hopping conduction. Addtionally, RTA treatment was introduced to improve the Sn-dopped SiO2 films. It could also reduce leakage current of devices after RTA treatment. At last, we used constant current forming to find the process of electrons hopping conduction.
8

Vers les sources optiques compatibles CMOS: corrélation entre élaboration et propriétés des nanocristaux de Si pas LPCVD

Koukos, Konstantinos 15 December 2009 (has links) (PDF)
Les systèmes sur puce comportant des fonctions optiques ont un vif intérêt pour les futures générations de systèmes embarqués, les telecommunications, l'instrumentation. La faisabilité d'une source silicium compatible avec la technologie CMOS reste à ce jour un verrou majeur pour ouvrir la voie à des systèmes optoélectroniques intégrés. L'utilisation des nanocristaux de silicium dans une matrice de SiO2 est actuellement une voie prometteuse visant à lever ce verrou. L'objectif de cette thèse est d'étudier la faisabilité de sources émettant dans le visible/proche infrarouge à base de nanocristaux de silicium, en explorant les potentialités de dépôts LPCVD (Low Pressure Chemical Vapor Deposition). En partant de l'étude des propriétés des nanocristaux, une approche bottom-up a été choisie pour la réalisation des composants de test. Un procédé d'élaboration du matériau actif, compatible avec la technologie CMOS, a été mis au point et nous a permis d'obtenir de façon reproductible des nanocristaux avec les propriétés souhaitées. Les mécanismes d'émission lumineuse ont été étudiés et corrélés avec les propriétés structurales et électriques. Une émission lumineuse intense a été obtenue sous excitation optique. L'obtention d'électroluminescence nécessite quant à elle une optimisation spécifique tant au niveau matériau qu'au niveau procédé technologique. A cette fin, plusieurs voies ont été explorées nous conduisant à établir le compromis entre propriétés optiques et électriques. Au terme de cette étude, nous avons évalué les avantages et inconvénients de cette technique d'élaboration et proposons des solutions pour parvenir à fabriquer un dispositif électroluminescent fonctionnel.
9

Scheduling for a Large-Scale Production System Based on a Continuous and Timed Petri-Net Model

OKUMA, Shigeru, SUZUKI, Tatsuya, INABA, Akio, KIM, YoungWoo 01 March 2003 (has links)
No description available.
10

Arrival and departure manager cooperation for reducing airborne holding times at destination airports

Rydell, Sofia 08 1900 (has links)
This thesis addresses the possibility of using a delay-on-ground concept in which flights with less than 1 hour flying time (often referred to as pop-up flights) absorb their arrival sequencing delay at the departure gate by being issued their Arrival Manager (AMAN)-scheduled time as a Required Time of Arrival (RTA) that is inserted into the Flight Management System (FMS). Due to their short duration these flights are currently often inserted into the AMAN sequence shortly before Terminal Manoeuvring Area (TMA) entry and thereby often need to absorb their arrival sequencing delay in the inefficient manner of airborne holding or vectoring close to the arrival airport. The literature review examines current operational procedures of AMANs and Departure Managers (DMANs), the current FMS RTA function and live trials in which the delay-on-ground concept was tested in real operations. A case study airport in Europe that has potential to benefit from the concept is identified. The performance of the delay-on-ground concept for the case study airport is then assessed by performing 180 fast-time Monte Carlo simulation runs. For each run the arrival flow to the case study airport and the departure flows from two medium-sized airports from which the pop-up flights originate are simulated. Each run represents an operational day and variations in departure/arrivals time is put into the timetables to simulate the variation in actual departure/arrival times resulting from operational factors normally encountered in day-to-day operations. An algorithm is written in Matlab to simulate an AMAN-DMAN cooperation in which pop-up flights are locked to the required departure times to meet their RTAs. It is shown that a significant reduction in airborne delay time and fuel consumption can be achieved at the case study airport by using the concept. It is also shown that it is possible to ensure that the pop-up flights depart at the required times to meet their RTAs without negatively affecting the departure sequences.

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