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A higher degree of system level integration can be achieved by integrating the passive components into semiconductor devices, which seem to be an enabling technology for portable communication and modern electronic devices. Greater functionality, higher performance and increase in reliability can be achieved by miniaturizing and reducing the number of components in integrated circuits. The functional potential of small electronic devices can be enormously increased by implementing the embedded capacitors, resistors and inductors. This would free up surface real estate allowing either a smaller footprint or more silicon devices to be placed on the same sized substrate. This thesis focuses on the effect of deposition temperature and post deposition annealing (PDA) in different gas ambient on the electrical properties of sputter deposited ferroelectric Barium Strontium Titanate (Ba0.5St0.5) TiO3 thin film capacitors. Approximately 2000A of Barium Strontium Titanate (BST) thin film was deposited at different substrate temperatures (400,450,500 and 550[degrees]C) on cleaned silicon substrates. These BST films were then annealed separately in 100% N2, 100% O2 and 10% O2 + 90% N2 at 575[degrees]C in sputtering machine (PVD anneal) and a three zone annealing Lindberg furnace. The objective of this thesis was to compare the effect of PDA on the electrical properties of BST films deposited at different substrate temperatures between PVD annealing and furnace annealing. For this work, tantalum thin film was used as top and bottom electrode to fabricate the capacitors. BST thin film capacitors were fabricated and characterized for leakage current and dielectric breakdown. Roughness study on pre and post annealed BST films were done using optical profilometer. The capacitors were tested using HP impedance analyzer in the frequency range from 10Hz through 1 MHz. From the experiments, 100% O2 annealed furnace annealed BST thin film seem to have better dielectric constant, higher breakdown voltage and nominal capacitance density.

With the rapid increase in miniaturization of mechanical components, the need for a hard, protective coatings is of great importance. In this study we investigate some of the mechanical, chemical and physical properties of the SiCN thin films. Thin films of amorphous silicon carbide nitride (a-SiCxNy) were deposited in a RF magnetron sputtering system using a powder pressed SiC target. Films with various compositions were deposited on to silicon substrate by changing the N2/Ar gas ratios during sputtering. Nano-indentation studies were performed to investigate the mechanical properties such as hardness and reduced modulus of the SiCN films. Surface morphology of the films was characterized by using atomic force microscopy (AFM). X-ray photoelectron spectroscopy (XPS) data indicated that the chemical status is highly sensitive to the nitrogen ratios during sputtering. Further, the films were annealed in dry oxygen ambient in the temperature range of 400 – 900°C and characterized using XPS to investigate the chemical composition and oxidation kinetics at each annealing temperature. The surface roughness of these films was studied as a function of annealing temperature and film composition with the help of a "Veeco" optical profilometer. Nano-indentation studies indicated that the hardness and the reduced modulus of the film are sensitive to the N2/Ar ratio of gas flow during sputtering. AFM studies revealed that the films become smoother as the N2/Ar ratio is increased. XPS data indicated the existence of C-N phases in the as-deposited films. The study of oxidation kinetics of RF sputter deposited SiCN thin films, using XPS, suggest that N2 co-sputtering helps to suppress the formation of a surface oxide, by allowing un-bonded Si to bond with N and C inside the vacuum chamber as opposed to bonding with O in atmosphere.

During evacuations, emergency managers and departments of transportation seek to facilitate the movement of citizens out of impacted or threatened areas. One strategy they may consider is crossing elimination, which prohibits certain movements at intersections, that may be permissible under normal operating conditions. A few previous studies examined this strategy in conjunction with contra-flow operations, but fewer have considered crossing elimination by itself. This study helps fill the existing gap in knowledge of the individual effects of crossing elimination. A bi-level model that iterates between optimization and simulation is developed to determine the optimal configuration of intersection movements from a set of pre-specified possible configurations for intersections in a given area. At the upper level, evacuees' travel time is minimized and at the lower level, traffic is assigned to the network with the traffic assignment-simulation software DynusT. The overall model is solved with a simulated annealing heuristic and applied to a real case study to assess the impact of crossing elimination. Three scenarios are developed and examined using the solution method proposed in this research. These scenarios are developed using combinations of two elements: (1) Evacuee destination distributions, and (2) Evacuee departure time distributions. Results showed about 3-5 percent improvement in total evacuee travel time can be achieved in these scenarios. Availability of through movements at intersections and existing merging points in movement configurations are the two factors influencing the selection of movement configurations. / Master of Science

<p> This project is concerned with medium energy heavy ion (60 KEV 75As, 40Ar, 120 KEV 150As2) implantation into single crystal iron at room temperature and 35°K. Resulting crystal properties are measured using the technique of high energy light ion (1.0 MEV 4He) channeling and backscattering. The phenomenon of oxygen recoil implantation by the bombarding ion is found to be an important effect to avoid if radiation damage is to be measured. In cases where oxygen recoil implantation has been eliminated, radiation damage was evident from an increase in the minimum channeling yield. The existence of damage beyond the expected damage range at room temperature is attributed to diffusion of defects. Some annealing of damage is observed in samples which have been damaged at 35°K and warmed to room temperature. At doses of about 10^16 atoms/cm^2, 80(±10)% of the implanted As is found to be at lattice sites.</p> <p> The merits and limitations of this technique as a simulation of 14 MEV neutron radiation damage are also discussed.</p> / Thesis / Master of Engineering (MEngr)

Gallium oxide (Ga2O3) has been the subject of extensive research activity due to its ultrawide bandgap and large breakdown field, which make it promising for next-generation applications in deep ultraviolet detection and power electronics. β-Ga2O3 is the most thermally stable and well-studied polymorph of Ga2O3. However, during the past decade, the metastable orthorhombic κ-Ga2O3 has emerged as an equally impressive candidate material owing to its high crystal symmetry and ferroelectric and spontaneous polarization properties. Several studies have reported the growth and characterization of κ-Ga2O3 films using different epitaxial growth methods. However, the existing literature still lacks reports on the processing of this material for future device applications. Therefore, in this thesis, we investigate the effects of high-temperature treatment and plasma exposure on the structural and optical properties of mist chemical vapor deposition (mist-CVD)-grown κ-Ga2O3 films. Using high-temperature X-ray diffraction (HT-XRD), we show that the films remain phase-pure up to an annealing temperature of 800 ˚C, after which β-phase peaks start to appear and eventually show a complete transition to β-Ga2O3 at 875 ˚C. Additionally, we show using detailed high-resolution transmission electron microscopy (HRTEM) and XRD analyses that annealing at 700 ˚C in ambient air is effective in improving the crystal quality of the κ-Ga2O3 layer by relieving in-plane strains and epitaxial stacking faults. Moreover, since dry etching is needed for the anisotropic patterning of materials for device applications, it is necessary to investigate the effects of plasma exposure on the near-surface properties of the material in order to keep its damage to a minimum. Therefore, we studied the impacts of plasma exposure during dry etching on the chemical structure, crystallinity, and optical properties of κ-Ga2O3 by using a variety of characterization methods. We observed how varying the etching parameters using BCl3/Ar can affect the near-surface properties of the material, which play a key role in modifying the performance of future devices. Specifically, we found that both RIE/ICP power and BCl3/Ar ratio can influence the surface stoichiometry and the concentration of native defect density, which affect the material’s structural and optical properties. Additionally, we reported for the first time on κ-Ga2O3 ICP-RIE process optimization using a BCl3/Ar gas mixture. By tuning the process parameters, the optimized recipe had a high etch rate of 130 nm/min, showed a surface roughness reduction of 56%, and produced vertical sidewall profiles for ridge device structures.

This thesis focuses on an adaptive quadratic spiking model of a motoneuron that is both versatile in its ability to represent a range of experimentally observed neuronal firing patterns as well as computationally efficient for large network simulation. The objective of research is to fit membrane voltage data to the model using a parameter estimation approach involving simulated annealing. By manipulating the system dynamics of the model, a realizable model with linear parameterization (LP) can be obtained to simplify the estimation process. With a persistently excited current input applied to the model, simulated annealing is used to efficiently determine the best model parameters that minimize the square error function between the membrane voltage reference data and data generated by the LP model. Results obtained through simulation of this approach show feasibility to predict a range of different neuron firing patterns.

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