The Influence of Alternative Electrode Configurations and Process Integration Schemes on IGZO TFT Operation

Amorphous oxide semiconductors (AOS) have been extensively studied for their application in thin-film electronics; an area which is currently dominated by hydrogenated amorphous silicon (a Si:H) technology. Indium-gallium-zinc oxide (IGZO) has garnered most of the AOS materials focus due to its high carrier mobility and process simplicity. When modifying an existing process flow for fabrication of TFTs, the effect of each modification on the electrical characteristics must be determined. The compatibility of the process with the constraints of a glass substrate must also be considered. A new test chip layout was created that enables the fabrication of TFTs with a variety of electrode configurations including top-gate, bottom-gate, double-gate, and either staggered or co-planar source/drain regions. TFTs were fabricated on glass and oxidized silicon substrates, consisting of sputter-deposited IGZO surrounded by SiO2 dielectric layers, an oxidizing ambient anneal treatment, and a capping layer deposited by atomic layer deposition (ALD). Electrical characteristics from each process treatment and gate configuration were compared, with some noted differences in device operation related to process integration. A SPICE level 2 compatible IGZO TFT model was developed, with extracted parameter values providing quantitative measures for comparison

Bicycle Parking in Chapel Hill, North Carolina: Where It's At and Where It's Going

Chapel Hill, North Carolina, is a bustling college town with a great number of bicyclists, yet bicycle parking is a largely neglected topic by both its Code of Ordinances and its transportation planning staff. This project seeks to change that. Over six months in 2020, I collected a fieldwork inventory of almost all bicycle parking and maintenance resources within Town limits. I published this inventory as a public-facing interactive map and used it internally to perform a site-level analysis of adherence to the Town’s bicycle parking capacity requirements and design guidelines. I then evaluated the results of this analysis and consulted bicycle parking requirements in five United States municipalities similar to Chapel Hill to formulate recommendations to Town planning staff on improving their own codified bicycle parking requirements. My findings suggest that at least half of all sites in Chapel Hill have been violating bicycle parking capacity requirements and that almost all of them have been violating design guidelines, with the most common offense being an unsatisfactory amount of long-term parking. With my assistance, the Town of Chapel Hill Planning Department will use this dataset to amend bicycle parking capacity requirements and design guidelines in the Town’s Land Use Management Ordinance. The dataset will also be useful to all Chapel Hill bicyclists for more reliably locating bicycle parking at their destinations, making the Town of Chapel Hill a more bicycle-friendly place to live, work, and visit.Master of City and Regional Plannin

Measurement of femtosecond Polarization Mode Dispersion (PMD) using biased p-shifted low-coherence interferometry.

Conventional low-coherence interferometry (LCI) can be employed in the measurement of polarization mode dispersion (PMD) of fiber-optic components and fibers. However, the smallest PMD, which can be measured using this technique, is limited by the coherence length of the source. We propose a biased p-shifted Michelson interferometer where a birefringent crystal is inserted in front of the interferometer to introduce a bias differential group delay (DGD) larger than the coherence time of the source. In this way, the limitation imposed by the source coherence time has been overcome and PMDs much smaller than the source coherence time, in the order of several femtoseconds, can be measured. Experimental results for the PMD have been shown and compared with Jones matrix eigen-analysis. The theoretical model confirms the experimental observations

Donor activation in boron and phosphorus implanted self-aligned bottom-gate Igzo Tfts

Self-aligned channel regions in thin-film transistors (TFTs) have advantages in reduced parasitic capacitance and stage delay, and a reduction in overhead real estate. A common method used to fabricate self-aligned a‑Si:H TFTs is to utilize a through-glass exposure of photoresist which is blocked by the opaque metal bottom-gate electrode [1,2]. This process does not require an additional photomask or lithographic alignment, and thus supports low production cost. Sputtered IGZO has been introduced into flat panel display product manufacturing, exhibiting a channel mobility of approximately an order of magnitude higher than a-Si:H. The working source/drain electrodes in IGZO TFTs can be direct metal contact regions to the IGZO, without the need for additional processes such as doping to render the IGZO conductive. Proper metallurgy and annealing processes can provide ohmic behavior with minimal series resistance, however this usually requires several microns of gate-to-source/drain overlap to ensure such behavior. Please click Download on the upper right corner to see the full abstract

Maternal mental health:a key area for future research among women with congenital heart disease

In this viewpoint, we respond to the recently published national priorities for research in congenital heart disease (CHD) among adults, established through the James Lind Alliance Priority Setting Partnership, with specific attention to priority 3 (mental health) and priority 5 (maternal health). Our recent policy impact project explored how maternal mental health is currently addressed in adult congenital heart disease (ACHD) services in the National Health Service, identified gaps and discussed possible ways forward. Our multidisciplinary discussion groups, which included women with lived experience of CHD and pregnancy, cardiology and obstetrics clinicians and medical anthropologists, found that while pregnancy and the postnatal period increase the mental health challenges faced by women with CHD, current services are not yet equipped to address them. Based on this work, we welcome the prioritisation of both mental health and maternal health in ACHD, and suggest that future research should focus on the overlaps between these two priority areas

Genome-wide Association Analysis Identifies 14 New Risk Loci for Schizophrenia

Schizophrenia is a heritable disorder with substantial public health impact. We conducted a multi-stage genome-wide association study (GWAS) for schizophrenia beginning with a Swedish national sample (5,001 cases, 6,243 controls) followed by meta-analysis with prior schizophrenia GWAS (8,832 cases, 12,067 controls) and finally by replication of SNPs in 168 genomic regions in independent samples (7,413 cases, 19,762 controls, and 581 trios). In total, 22 regions met genome-wide significance (14 novel and one previously implicated in bipolar disorder). The results strongly implicate calcium signaling in the etiology of schizophrenia, and include genome-wide significant results for CACNA1C and CACNB2 whose protein products interact. We estimate that ∼8,300 independent and predominantly common SNPs contribute to risk for schizophrenia and that these collectively account for most of its heritability. Common genetic variation plays an important role in the etiology of schizophrenia, and larger studies will allow more detailed understanding of this devastating disorder

No Reliable Association between Runs of Homozygosity and Schizophrenia in a Well-Powered Replication Study

It is well known that inbreeding increases the risk of recessive monogenic diseases, but it is less certain whether it contributes to the etiology of complex diseases such as schizophrenia. One way to estimate the effects of inbreeding is to examine the association between disease diagnosis and genome-wide autozygosity estimated using runs of homozygosity (ROH) in genome-wide single nucleotide polymorphism arrays. Using data for schizophrenia from the Psychiatric Genomics Consortium (n = 21,868), Keller et al. (2012) estimated that the odds of developing schizophrenia increased by approximately 17% for every additional percent of the genome that is autozygous (β = 16.1, CI(β) = [6.93, 25.7], Z = 3.44, p = 0.0006). Here we describe replication results from 22 independent schizophrenia case-control datasets from the Psychiatric Genomics Consortium (n = 39,830). Using the same ROH calling thresholds and procedures as Keller et al. (2012), we were unable to replicate the significant association between ROH burden and schizophrenia in the independent PGC phase II data, although the effect was in the predicted direction, and the combined (original + replication) dataset yielded an attenuated but significant relationship between Froh and schizophrenia (β = 4.86,CI(β) = [0.90,8.83],Z = 2.40,p = 0.02). Since Keller et al. (2012), several studies reported inconsistent association of ROH burden with complex traits, particularly in case-control data. These conflicting results might suggest that the effects of autozygosity are confounded by various factors, such as socioeconomic status, education, urbanicity, and religiosity, which may be associated with both real inbreeding and the outcome measures of interest

Contribution of copy number variants to schizophrenia from a genome-wide study of 41,321 subjects

Copy number variants (CNVs) have been strongly implicated in the genetic etiology of schizophrenia (SCZ). However, genome-wide investigation of the contribution of CNV to risk has been hampered by limited sample sizes. We sought to address this obstacle by applying a centralized analysis pipeline to a SCZ cohort of 21,094 cases and 20,227 controls. A global enrichment of CNV burden was observed in cases (OR=1.11, P=5.7×10−15), which persisted after excluding loci implicated in previous studies (OR=1.07, P=1.7 ×10−6). CNV burden was enriched for genes associated with synaptic function (OR = 1.68, P = 2.8 ×10−11) and neurobehavioral phenotypes in mouse (OR = 1.18, P= 7.3 ×10−5). Genome-wide significant evidence was obtained for eight loci, including 1q21.1, 2p16.3 (NRXN1), 3q29, 7q11.2, 15q13.3, distal 16p11.2, proximal 16p11.2 and 22q11.2. Suggestive support was found for eight additional candidate susceptibility and protective loci, which consisted predominantly of CNVs mediated by non-allelic homologous recombination

Age at first birth in women is genetically associated with increased risk of schizophrenia

Prof. Paunio on PGC:n jäsenPrevious studies have shown an increased risk for mental health problems in children born to both younger and older parents compared to children of average-aged parents. We previously used a novel design to reveal a latent mechanism of genetic association between schizophrenia and age at first birth in women (AFB). Here, we use independent data from the UK Biobank (N = 38,892) to replicate the finding of an association between predicted genetic risk of schizophrenia and AFB in women, and to estimate the genetic correlation between schizophrenia and AFB in women stratified into younger and older groups. We find evidence for an association between predicted genetic risk of schizophrenia and AFB in women (P-value = 1.12E-05), and we show genetic heterogeneity between younger and older AFB groups (P-value = 3.45E-03). The genetic correlation between schizophrenia and AFB in the younger AFB group is -0.16 (SE = 0.04) while that between schizophrenia and AFB in the older AFB group is 0.14 (SE = 0.08). Our results suggest that early, and perhaps also late, age at first birth in women is associated with increased genetic risk for schizophrenia in the UK Biobank sample. These findings contribute new insights into factors contributing to the complex bio-social risk architecture underpinning the association between parental age and offspring mental health.Peer reviewe

Genetic correlation between amyotrophic lateral sclerosis and schizophrenia

A. Palotie on työryhmän Schizophrenia Working Grp Psychiat jäsen.We have previously shown higher-than-expected rates of schizophrenia in relatives of patients with amyotrophic lateral sclerosis (ALS), suggesting an aetiological relationship between the diseases. Here, we investigate the genetic relationship between ALS and schizophrenia using genome-wide association study data from over 100,000 unique individuals. Using linkage disequilibrium score regression, we estimate the genetic correlation between ALS and schizophrenia to be 14.3% (7.05-21.6; P = 1 x 10(-4)) with schizophrenia polygenic risk scores explaining up to 0.12% of the variance in ALS (P = 8.4 x 10(-7)). A modest increase in comorbidity of ALS and schizophrenia is expected given these findings (odds ratio 1.08-1.26) but this would require very large studies to observe epidemiologically. We identify five potential novel ALS-associated loci using conditional false discovery rate analysis. It is likely that shared neurobiological mechanisms between these two disorders will engender novel hypotheses in future preclinical and clinical studies.Peer reviewe