Nanoscale strain characterisation of modern microelectronic devices

PhD ThesisSources of stress and strain in modern microelectronics can be either beneficial to the electrical performance or detrimental to the mechanical integrity and ultimately lifetime of the device. Strain engineering is commonplace in state-of-the-art device fabrication as a means to boost performance in the face of device scaling limitation. The strain present in the device is directly related to the improvement factor and as such precise measurements and good understanding are of utmost importance due to the many thermal processing steps that can induce or cause relaxation of the strain. Front-end-of-line (FEOL) strain characterisation is becoming increasingly challenging due to the small volumes of material and nanoscale feature sizes being analysed. In this work, an extensive survey of strain characterisation techniques was undertaken. Narrow sSOI stripes were profiled using conventional Raman spectroscopy. Unlike with previous studies, it was shown that it is possible to achieve nanoscale measurements using current techniques. This study was supported by ANSYS FE simulation. The review of the literature briefly investigates the possibility of EBSD as a strain measurement tool. It is possible to calculate not just an absolute strain value as achievable with Raman spectroscopy, but the strain tensor. However, this is a difficult and complex process and not necessary for use in industry. This study proposes the possibility of a more simple method that would provide a good calibration technique to confirm Raman measurements. SERS and TERS are explored in detail as the most promising techniques when dealing with device scaling. Currently, SERS is a destructive technique not suitable for use in a highly cost driven industry such as semiconductor manufacturing. While it theoretically gives improved surface selectivity over conventional Raman spectroscopy, there is no improvement to the xy spatial resolution. With Si and SiGe samples, this study concludes there is also often no surface selectivity with either technique and the mechanisms behind the enhancement are not understood to the point of being able to implement the techniques in a process line. However, where a non-destructive technique is desired, outlined in this study is a method of achieving the SERS effect without sacrificing the sample. Aggressive scaling has forced the dimensions of the interconnecting wires that give the devices functionality to the deep submicron range. Copper, Cu has been introduced as a replacement to the traditionally used aluminium, Al because of its superior electrical and mechanical properties and scalability. However, as these wires begin to approach the dimensions of thin foils, the microtexture of the wires becomes significantly different from their bulk counterparts. This can affect the mechanical integrity of the interconnects and this has an impact on the reliability of the device. Failure mechanisms such as blistering, cracking and peeling caused by stress and strain are not uncommon and traditional methods of characterising residual stress in the thin films is no longer applicable to these narrow wires. The mechanical properties and microtexture of thin copper films annealed at temperatures comparative to those found in device manufacturing were characterised in some detail. EBSD was used to determine the grain size and structure of the films before nanoindentation confirmed properties such as hardness and elastic modulus. These results pave the way for investigation of strain applied along deep-submicron interconnects to lead to further understanding of what causes failure mechanisms from interconnecting wires

Comment, Discrimination in Access to Public Places: A Survey of State and Federal Public Accommodations Laws

The purpose of this Project is to chart recent developments in public accommodations law, including the expansion of access rights to places not previously regarded as public, the proscription of discrimination against groups other than racial minorities, and the increasing role of the state civil rights commissions in enforcing discrimination law. This survey provides a basis for assessing the adequacy of existing remedies and suggests changes in state and federal law. The Project conducts a mechanical examination of the statutes on the books. It does not discuss how those laws came into existence or the actual workings of the agencies which enforce them

The blood–brain barrier significantly limits eflornithine entry into Trypanosoma brucei brucei infected mouse brain1

Drugs to treat African trypanosomiasis are toxic, expensive and subject to parasite resistance. New drugs are urgently being sought. Although the existing drug, eflornithine, is assumed to reach the brain in high concentrations, little is known about how it crosses the healthy and infected blood–brain barrier. This information is essential for the design of drug combinations and new drugs. This study used novel combinations of animal models to address these omissions. Eflornithine crossed the healthy blood–CNS interfaces poorly, but this could be improved by co-administering suramin, but not nifurtimox, pentamidine or melarsoprol. Work using a murine model of sleeping sickness demonstrated that Trypanosoma brucei brucei crossed the blood–CNS interfaces, which remained functional, early in the course of infection. Concentrations of brain parasites increased during the infection and this resulted in detectable blood–brain barrier, but not choroid plexus, dysfunction at day 28 post-infection with resultant increases in eflornithine brain delivery. Barrier integrity was never restored and the animals died at day 37.9 ± 1.2. This study indicates why an intensive treatment regimen of eflornithine is required (poor blood–brain barrier penetration) and suggests a possible remedy (combining eflornithine with suramin). The blood–brain barrier retains functionality until a late, possibly terminal stage, of trypanosoma infection

Improving long-term disaster recovery research in Australia through boosting dataset comparability

Emergencies and disasters are increasing in frequency and complexity in Australia and around the world.1 It is well established that the effects of these events take a long time to recover from. There is strong and growing evidence to show that different segments of society are exposed to disasters in different ways, with people and communities affected in interconnected and compounding ways

Nursing, Indigenous Health, Water, and Climate Change

Nurses have a duty to uphold the right to health. Clean water is vital for health as an inclusive right for all people, yet access is threatened by climate change. Complex impacts of colonization on climate change has resulted in two key problems: lack of clean water access by Indigenous Peoples and marginalization of Indigenous traditional teachings that support water protection. Indigenous teachings of living in harmony with Mother Earth are important contributions to global water policy and health solutions.  Indigenous traditional laws on water protection may be understood through Indigenous water declarations. Nurses have an important opportunity to respect traditional teachings noting interconnections of health, water, and climate change to advance health. Water is life

Unannounced telephone pill counts for assessing varenicline adherence in a pilot clinical trial

Nia Thompson1, Niaman Nazir1, Lisa Sanderson Cox1,2, Babalola Faseru1,2, Kathy Goggin3, Jasjit S Ahluwalia4, Nicole L Nollen1,21University of Kansas School of Medicine, Department of Preventive Medicine and Public Health, Kansas City, KS, USA; 2University of Kansas Cancer Center, Kansas City, KS, USA; 3University of Missouri-Kansas City, Department of Psychology, Kansas City, MO, USA; 4University of Minnesota Medical School, Department of Medicine and Center for Health Equity, Minneapolis, MN, USABackground: Despite consistent evidence linking smoking cessation pharmacotherapy adherence to better outcomes, knowledge about objective adherence measures is lacking and little attention is given to monitoring pharmacotherapy use in smoking cessation clinical trials.Objectives: To examine unannounced telephone pill counts as a method for assessing adherence to smoking cessation pharmacotherapy.Research design: Secondary data analysis of a randomized pilot study.Participants: 46 moderate-to-heavy (>10 cigarettes per day) African-American smokers.Main measures: Smokers received 1 month of varenicline (Pfizer Global Pharmaceuticals, New York, NY) in a pill box at baseline. Unannounced pill counts were completed by telephone 4 days prior to an in-person pill count conducted at Month 1. At both counts, each compartment of the pill box was opened and the number of remaining pills was recorded.Results: Participants were a mean age of 48 years (SD = 13), predominately female (59%), low income (60% < $1800 monthly family income), and smoked an average of 17 (SD = 7) cigarettes per day. A high degree of concordance was observed between the number of pills counted by phone and in-person (rs = 0.94, P < 0.001). Participants with discordant counts (n = 7) had lower varenicline adherence (mean [SD] = 77% [18%] vs 95% [9%], P < 0.0005), but reported better medication adherence in the past (1.0 [0.8] vs 2.8 [1.0], P < 0.0004) than participants with matching phone and in-person counts (n = 39).Conclusion: Unannounced telephone pill counts appear to be a reliable and practical method for measuring adherence to smoking cessation pharmacotherapy.Keywords: medication adherence, African-Americans, smoking cessatio

The Role of Neighborhood Experiences in Psychological Distress among African American and White Smokers

Residential area characteristics and discrimination have been associated with psychological distress. Differences in these relationships across racial groups are not well understood. We examined the relative role of perceived discrimination, neighborhood problems, and neighborhood cohesion/trust in explaining differences in psychological distress (indicated by anxiety and depressive symptoms) between 224 African American and 225 white smokers (income ≤ 400% federal poverty level) in a smoking cessation intervention study. Surveys were linked to US census tract data. We conducted random intercept Poisson multilevel regression models and examined interactions between race and neighborhood experiences. African Americans had greater risk of anxiety and depressive symptoms and greater individual and neighborhood disadvantage than whites. Controlling for objective neighborhood characteristics, when perceived discrimination and perceived neighborhood characteristics were added to the regression models, the association between anxiety symptoms and race were no longer statistically significant; the association between depressive symptoms and race decreased, but remained statistically significant. Lower neighborhood social cohesion/trust and greater neighborhood problems increased depressive symptoms for African Americans, but not for whites. Perceived discrimination and neighborhood social cohesion/trust outweighed the importance of race in explaining anxiety symptoms. These findings underscore the need for multilevel interventions addressing social and environmental contexts