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Performance enhancement in column IV mobility, bandgap, and strain engineered MOSFETsOnsongo, David Masara, 1972- 26 July 2011 (has links)
Not available / text
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A study of thermally nitrided silicon dioxide thin films for metal-oxide-silicon VLSI techology劉志宏, Liu, Zhihong. January 1990 (has links)
published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
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Cold-wall low-pressure chemical-vapor-deposited silicon nitride for use as the undergate dielectric in field-effect transistors by David Robert Clark.Clark, David Robert January 1981 (has links)
No description available.
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Organic semiconductors for self-assembled monolayer field effect transistorsLu, Kexin January 2012 (has links)
Molecular self-assembly has recently attracted significant attention for possible application in organic electronic and optoelectronic devices, such as self-assembled monolayer field-effect transistors (SAMFETs) and functional self-assembled integrated circuits. Self-assembly combines the advantages of low temperature solution processability, regio-selective monolayer adsorption and nano-scale control of film thickness. Much progress has been made in improving device performance using self-assembled monolayers (SAMs). However, most SAMFET devices reported to date showed current modulation only with submicrometre channels, with low device yields and poor reproducibility as a result of limited lateral interconnection of the semiconducting layer.In an attempt to address these issues, this thesis presents an investigation of the synthesis and properties of conjugated SAM molecules for use as the charge transporting layer in SAMFETs. Chapter 1 gives a comprehensive introduction to SAM-based surface systems, organic semiconductors and their use in OFETs and SAMFETs. Chapter 2 discusses attempts to design and synthesise p-type conjugated molecules capable of self-assembly on oxide surfaces based on a phenylene-bithiophene semiconducting core. The optical and electrochemical properties, as well as the thermal behaviour of these molecules are studied in detail. This theme is carried over to Chapter 3, which describes the synthesis, chemical and physical characterisation of two families of n-type SAM molecules. These molecules consist of NTCDI cores with hexyl or cyclohexyl chains as end-capping groups. Incorporation of a selection of materials as the active layer in OFETs or SAMFETs to evaluate the charge transport is demonstrated in Chapter 4. Monolayer films based on p-type monochlorosilane-terminated SAM molecules are made using the solution assembly technique and characterised by contact angle and AFM. OFETs made from DH-PTTP by both thermal evaporation and spin coating show high mobilities comparable to the best values reported in the literature. Top-contact SAMFETs show a hole mobility of 1.1 × 10-3 cm2V-1s-1 in air, consistent with those of solution processed DH-PTTP based OFETs. Finally, an overview of the project and some suggestions for future work are presented in Chapter 5.
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Low-temperature-grown InGaAs quantum wells for optical device applicationsJuodawlkis, Paul W. 05 1900 (has links)
No description available.
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High-frequency performance projections and equivalent circuits for carbon-nanotube transistorsPaydavosi, Navid Unknown Date
No description available.
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Computer-aided design of RF MOSFET power amplifiers.Hoile, Gary Alec. January 1992 (has links)
The process of designing high power RF amplifiers has in the past relied heavily on
measurements, in conjunction with simple linear theory. With the advent of the
harmonic balance method and increasingly faster computers, CAD techniques can be
of great value in designing these nonlinear circuits.
Relatively little work has been done in modelling RF power MOSFETs. The methods
described in numerous papers for the nonlinear modelling of microwave GaAsFETs
cannot be applied easily to these high power devices. This thesis describes a
modelling procedure applicable to RF MOSFETs rated at over 100 W. This is
achieved by the use of cold S parameters and pulsed drain current measurements
taken at controlled temperatures. A method of determining the required device
thermal impedance is given.
A complete nonlinear equivalent circuit model is extracted for an MRF136
MOSFET, a 28 V, 15 W device. This includes two nonlinear capacitors. An
equation is developed to describe accurately the drain current as a function of the
internal gate and drain voltages. The model parameters are found by computer
optimisation with measured data. Techniques for modelling the passive components
in RF power amplifiers are given. These include resistors, inductors, capacitors, and
ferrite transformers. Although linear ferrite transformer models are used, nonlinear
forms are also investigated.
The accuracy of the MOSFET model is verified by comparison to large signal
measurements in a 50 0 system. A complete power amplifier using the MRF136,
operating from 118 MHz to 175 MHz is built and analysed. The accuracy of
predictions is generally within 10 % for output power and DC supply current, and
around 30 % for input impedance. An amplifier is designed using the CAD package,
and then built, requiring only a small final adjustment of the input matching circuit.
The computer based methods described lead quickly to a near-optimal design and
reduce the need for extensive high power measurements. The use of nonlinear
analysis programs is thus established as a valuable design tool for engineers working
with RF power amplifiers. / Thesis (Ph.D.)-University of Natal, Durban, 1992.
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Growth of pentacene on parylene and on BCB for organic transistors application, and DNA-based nanostructures studied by Amplitude : Modulation Atomic Force Microscopy in air and in liquidsIazykov, Maksym 22 June 2011 (has links) (PDF)
This work reports the various aspects of the application of atomic force microscopy (AFM), for the characterization of organic semiconductors and DNA-based arrays, for organic electronics and biological applications. On these soft surfaces, the amplitude modulation AFM mode was chosen. This choice is argued by a study of dissipative processes, performed on a particular sample, a DNA chip. We showed the influence of experimental parameters on the topographic and phase image quality. By calculating the dissipative energy, it was shown that the dissipation on the DNA chip was mainly induced by a viscoelastic tip-sample interaction.The AFM study of the "thickness-driven" pentacene growth was made to link the morphology to the nature of the substrate and to the electrical performance of created pentacene-based Organic Field Effect Transistor (OFET). Deposited on two polymer substrates, parylene and benzocyclobutene (BCB), pentacene has been characterized for nanoscale film thicknesses between 6 and 60nm. It has been shown that the larger grains were created for a deposited thickness of 30nm. Spectroscopic AFM mode was used as an alternative to the method of contact angles, to measure local surface energy. Decrease of surface energy is characteristic of a more ordered surface and was measured for a thickness of 30 nm of pentacene deposited on both substrates. Models of statistical analysis of spectral images, based on the Power Spectrum Distribution (PSD) have been used to explain the morphology of pentacene films. In addition, these models have provided a comprehensive description not only of the accessible surface of the sample, but also of its internal structural properties. Highlighted in the models, the critical thickness of 30 nm corresponds to a transition from the orthorhombic phase to the triclinic phase for pentacene molecules deposited on parylene. Similarly, a polymorphic transition occurs on the BCB. On OFETs, based on pentacene on BCB, the largest mobility of 3.1x10-2 cm²/Vs corresponds to the pentacene layer of 30nm, that shows a better ordering of the orthorhombic molecular packing in comparison with the triclinic packing.The molecular arrangement of X and Y structures based on DNA was observed, by AFM, in air and in two buffer solutions of Tris and HEPES on a mica substrate. It was shown that the treatment of the mica by Ni2 + ions increases the strength of the DNA/substrate interaction and reduces the diffusivity of the molecules. In air, wired macromolecules containing one double-stranded structure are observed on untreated mica and macromolecules with a 2D geometry on pretreated mica. Onto a non-treated, the greater thermal motion of weakly bounded to mica DNA molecules leads to the rupture of intermolecular bonding and the forming structures are more simple and not branched. The organization is different in solutions of Tris and HEPES. In the Tris solution, containing Mg2+ cations, the arrangement leads to a well-organized 2D architecture. In the HEPES solution, containing Ni2+ cations, the ionic strength is 10 times lower, this leads to a breaking of the bonds previously formed between DNA and mica. However, DNA molecules are near each other due to a partial substitution of already adsorbed Mg2 + cations by Ni 2 + cations of higher affinity with the mica. These results show that the two liquids promote a 2D assembly. In air, the networks are not stable and the few observed ones remain in a dendritic structure on the surface of pretreated mica and as a linear macromolecule on the untreated mica.
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The epitaxial growth of GaN and A1GaN/GaN Heterostructure Field Effect Transistors (HFET) on Lithium Gallate (LiGaO₂) substratesKang, Sangbeom 12 1900 (has links)
No description available.
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Modeling hot-electron injection and impact ionization in pFET'sDuffy, Christopher James 12 1900 (has links)
No description available.
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