Continuous downscaling of transistor size has been the major trend of the semiconductor industry for the past half century. In recent years, however, fundamental physical limits to continued downscaling were encountered. In order to overcome these limits, the industry experimented --- and continues to experiment --- with many new materials and architectures. Non-invasive, in-line methods of characterizing critical properties of these structures are in demand. This dissertation develops optical second-harmonic generation (SHG) to characterize performance-limiting defects, band alignment or strain distribution in four advanced electronic material systems of current interest: (1) Hot carrier injection (HCI) is a key determinant of the reliability of ultrathin silicon-on-insulator (SOI) devices. We show that time-dependent electrostatic-field-induced SHG probes HCI from SOI films into both native and buried oxides without device fabrication. (2) Band offsets between advanced high-k gate dielectrics and their substrates govern performance-limiting leakage currents, and elucidate interfacial bond structure. We evaluate band offsets of as-deposited and annealed Al₂O₃, HfO₂ and BeO films with Si using internal photoemission techniques. (3) Epi-GaAs films grown on Si combine the high carrier mobility and superior optical properties of III-V semiconductors with the established Si platform, but are susceptible to formation of anti-phase boundary (APB) defects. We show that SHG in reflection from APB-laden epi-films is dramatically weaker than from control layers without APBs. Moreover, scanning SHG images of APB-rich layers reveal microstructure lacking in APB-free layers. These findings are attributed to the reversal in sign of the second-order nonlinear optical susceptibility [chi]⁽²⁾ between neighboring anti-phase domains, and demonstrate that SHG characterizes APBs sensitively, selectively and non-invasively. (4) 3D integration --- i.e. connecting vertically stacked chips with metal through-Si-vias (TSVs) --- is an important new approach for improving performance at the inter-chip level, but thermal stress of the TSVs on surrounding Si can compromise reliability. We present scanning SHG images for different polarization combinations and azimuthal orientations that reveal the sensitivity of SHG to strain fields surrounding TSVs. Taken together, these results demonstrate that SHG can identify performance-limiting defects and important material properties quickly and non-invasively for advanced MOSFET device applications. / text

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Published by the students of the College of Agriculture, University of Arizona.

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We investigate conditions for the ergodicity of threshold autoregressive time series by embedding the time series in a general state Markov chain and apply a FosterLyapunov drift condition to demonstrate ergodicity of the Markov chain. We are particularly interested in demonstrating V uniform ergodicity where the test function V () is a function of a norm on the statespace. In this dissertation we provide conditions under which the general state space chain may be approximated by a simpler system, whether deterministic or stochastic, and provide conditions on the simpler system which imply V uniform ergodicity of the general state space Markov chain and thus the threshold autoregressive time series embedded in it. We also examine conditions under which the general state space chain may be classified as transient. Finally, in some cases we provide conditions under which central limit theorems will exist for the V uniformly ergodic general state space chain.

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Background Vibrio infection (vibriosis) results from consuming contaminated seafood or exposing skin directly to marine waters or raw seafood. The Centers for Disease Control and Prevention (CDC) estimates that 80,000 illnesses occur each year in the United States. Four species, V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholerae (excluding toxigenic O1 and O139), are responsible for most cases. Understanding foodborne and non-foodborne transmission routes is important for describing epidemiological trends and for directing prevention efforts. Methods Demographic, clinical, and epidemiological data for cases reported between 1988 and 2012 were extracted from CDC’s Cholera and Other Vibrio Illness Surveillance System (COVIS). Outcomes and seasonal trends were described by species and transmission route. Results A total of 10,173 domestically acquired, non-toxigenic cases of vibriosis were reported, including 4,224 (41.5%) V. parahaemolyticus cases, 1,998 (19.6%) V. vulnificus cases, 1,267 (12.5%) V. alginolyticus cases, and 963 (9.5%) V. cholerae cases. There were 4,026 hospitalizations and 795 deaths reported. When categorized by transmission route, 5,775 (56.8%) cases were foodborne and 3,317 (32.6%) were non-foodborne.. Most (52.4%) cases occurred during the summer months with peaks in July and August. Only 140 cases were reported from eight states in 1988 compared to 907 cases reported by 42 states in 2012. The overall crude incidence in 2011 was 0.26 cases per 100,000 population. Discussion The number of reported cases of vibriosis has been increasing steadily since 1988. Increased prevention efforts, including safer seafood products and consumer education, are needed.These efforts should focus on specific populations and transmission routes for each of the top four species that cause most vibriosis cases in the United States.

The semiconductor alloy indium gallium nitride (InxGa1-xN) offers substantial potential in the development of high-efficiency multi-junction photovoltaic devices due to its wide range of direct band gaps, strong absorption and other optoelectronic properties. This work uses a variety of characterization techniques to examine the properties of InxGa1-xN thin films deposited in a range of compositions by a novel plasma-enhanced evaporation deposition system. Due to the high vapour pressure and low dissociation temperature of indium, the indium incorporation and, ultimately, control of the InxGa1-xN composition was found to be influenced to a greater degree by deposition temperature than variations in the In:Ga source rates in the investigated region of deposition condition space. Under specific deposition conditions, crystalline films were grown in an advantageous nano-columnar microstructure with deposition temperature influencing column size and density. The InxGa1-xN films were determined to have very strong absorption coefficients with band gaps indirectly related to indium content. However, the films also suffer from compositional inhomogeneity and In-related defect complexes with strong phonon coupling that dominates the emission mechanism. This, in addition to the presence of metal impurities, harms the alloy’s electronic properties as no significant photoresponse was observed. This research has demonstrated the material properties that make the InxGa1-xN alloy attractive for multi-junction solar cells and the benefits/drawbacks of the plasma-enhanced evaporation deposition system. Future work is needed to overcome significant challenges relating to crystalline quality, compositional homogeneity and the optoelectronic properties of In-rich InxGa1-xN films in order to develop high-performance photovoltaic devices. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2011-09-29 21:28:58.898

This thesis is a study of disputes and conflicts between officers and men in the Royal Navy between 1793 and 1814. The first part is a general introduction to shipboard life and work, discipline, resistance and protest, and to the sailors' culture and politics. The second part is a detailed study of the mutinies on the Culloden in 1794 and the Defiance in 1795, paying particular attention to the organization of the sailors, the strategy of the officers and the function and working of court martials. The third part is a more general history of the sailors' protests and mutinies between 1796 and 1814. These mutinies and protests are situated with regard to the changing balance of forces between officers and men in the Navy as a whole during these years. The thesis is largely based on the verbatim transcipts of court martials in the Royal Navy that are now part of the Admiratly Records at the Public Record Office. It is intended as a contribution to the social history of the Royal Navy and the labour history of the period.

The Vo sector of the vacuolar H+-ATPase is a multi-subunit complex that forms a proteolipid pore. The largest subunit in this complex is the a subunit which has four isoforms (a1-a4). The isoform(s) critical for secretory vesicle acidification has yet to be identified. Using a cell line derived from rat pheochromocytoma in which Voa1 and/or Voa2 had been down-regulated this study revealed that Voa1, and to a lesser extent, Voa2 are critical for acidifying dense-core vesicles (DCVs). The acidification defects resulting from down-regulation of Voa1 and Voa1/ Voa2 were suppressed by the expression of knockdown-resistant Voa1. Defects in DCV acidification resulted in reductions in their transmitter uptake and storage. Lastly, Ca2+-dependent peptide secretion appeared normal in Voa1 and Voa1/ Voa2 knockdown cells. . This study demonstrated that Voa1 and Voa2 cooperatively regulate dense-core vesicle acidification as well as transmitter uptake/storage, while they may not be critical for dense-core vesicle exocytosis.