Reducing Off-State and Leakage Currents by Dielectric Permittivity-Graded Stacked Gate Oxides on Trigate FinFETs: A TCAD Study.

Since its invention in the 1960s, one of the most significant evolutions of metal-oxide semiconductor field effect transistors (MOSFETs) would be the 3D version that makes the semiconducting channel vertically wrapped by conformal gate electrodes, also recognized as FinFET. During recent decades, the width of fin (Wfin) and the neighboring gate oxide width (tox) in FinFETs has shrunk from about 150 nm to a few nanometers. However, both widths seem to have been leveling off in recent years, owing to the limitation of lithography precision. Here, we show that by adapting the Penn model and Maxwell-Garnett mixing formula for a dielectric constant (κ) calculation for nanolaminate structures, FinFETs with two- and three-stage κ-graded stacked combinations of gate dielectrics with SiO2, Si3N4, Al2O3, HfO2, La2O3, and TiO2 perform better against the same structures with their single-layer dielectrics counterparts. Based on this, FinFETs simulated with κ-graded gate oxides achieved an off-state drain current (IOFF) reduced down to 6.45 × 10-15 A for the Al2O3: TiO2 combination and a gate leakage current (IG) reaching down to 2.04 × 10-11 A for the Al2O3: HfO2: La2O3 combination. While our findings push the individual dielectric laminates to the sub 1 nm limit, the effects of dielectric permittivity matching and κ-grading for gate oxides remain to have the potential to shed light on the next generation of nanoelectronics for higher integration and lower power consumption opportunities.

1 fm/Hz noise level low temperature Fabry-Pérot atomic force/magnetic force microscope operating in 4-300 K temperature range.

In this publication, we describe the design of a new fiber Fabry-Pérot interferometer and employ this to a low temperature atomic force/magnetic force microscope (LT-AFM/MFM) operating in the 4-300 K temperature range. A multilayer dielectric mirror coated optical fiber is used to achieve unprecedented 1 fm/Hz noise level, while the shot noise limit is 0.51 fm/Hz. The cavity length is adjustable, and the fiber can be brought within a very close proximity of the cantilever using a dedicated 2 mm stroke piezonanopositioner integrated on the piezotube scanner. The same nanopositioner also is used to park the fiber at a safe parking location during cantilever exchange. We demonstrate the performance of the LT-AFM/MFM by imaging the ITO thin film at 300 K, atomic steps on HOPG at 300 K, magnetic bits on the hard disk at 15 K, and the Abrikosov vortex lattice in the BSCCO(2122) single crystal at 4 K.

Interpretation of SARS-CoV-2 behaviour on different substrates and denaturation of virions using ethanol: an atomic force microscopy study.

Coronavirus (SARS-CoV-2) is a respiratory infection virus that was first detected in Wuhan, China. The virus causes COVID-19 disease and the outbreak was recognised as a pandemic by the World Health Organization (WHO) in March 2020. SARS-CoV-2 virion was first imaged using cryo-electron microscopy by the Chinese Center for Disease Control and Prevention (CDC). Atomic Force Microscopy is a unique technique that can allow imaging of biomolecules under different conditions. In this work, we used Atomic Force Microscopy to characterize SARS-CoV-2 on tissue culture polystyrene (TCPS) and glass coverslip surfaces. We isolated SARS-CoV-2 and drop casted it on coverslip glass and tissue culture polystyrene surfaces. We analyzed height profiles, density, and aggregation behavior of the virion on glass and polystyrene surfaces. We observed the coffee ring effect on the drop casted samples and close packing of virions near the coffee rings on both surfaces with relatively higher virion distribution on the tissue culture polystyrene (TCPS) substrates. We compare virion agglomeration on the two types of surfaces. Finally, we applied ethanol disinfectant to virions on the surface to visualize the effect of ethanol and image the ultrastructure of SARS-CoV-2.

Radiation pressure excitation of a low temperature atomic force/magnetic force microscope for imaging in 4-300 K temperature range.

We describe a novel radiation pressure based cantilever excitation method for imaging in dynamic mode atomic force microscopy (AFM) for the first time. Piezo-excitation is the most common method for cantilever excitation, however it may cause spurious resonance peaks. Therefore, the direct excitation of the cantilever plays a crucial role in AFM imaging. A fiber optic interferometer with a 1310 nm laser was used both for the excitation of the cantilever at the resonance and the deflection measurement of the cantilever in a commercial low temperature atomic force microscope/magnetic force microscope (AFM/MFM) from NanoMagnetics Instruments. The laser power was modulated at the cantilever's resonance frequency by a digital Phase Locked Loop (PLL). The laser beam is typically modulated by ∼500 µW, and ∼141.8 nmpp oscillation amplitude is obtained in moderate vacuum levels between 4 and 300 K. We have demonstrated the performance of the radiation pressure excitation in AFM/MFM by imaging atomic steps in graphite, magnetic domains in CoPt multilayers between 4 and 300 K and Abrikosov vortex lattice in BSCCO(2212) single crystal at 4 K for the first time.

An ultra-low temperature scanning Hall probe microscope for magnetic imaging below 40 mK.

We describe the design of a low temperature scanning Hall probe microscope (SHPM) for a dilution refrigerator system. A detachable SHPM head with 25.4 mm OD and 200 mm length is integrated at the end of the mixing chamber base plate of the dilution refrigerator insert (Oxford Instruments, Kelvinox MX-400) by means of a dedicated docking station. It is also possible to use this detachable SHPM head with a variable temperature insert (VTI) for 2 K-300 K operations. A microfabricated 1µm size Hall sensor (GaAs/AlGaAs) with integrated scanning tunneling microscopy tip was used for magnetic imaging. The field sensitivity of the Hall sensor was better than 1 mG/√Hz at 1 kHz bandwidth at 4 K. Both the domain structure and topography of LiHoF4, which is a transverse-field Ising model ferromagnet which orders below TC = 1.53 K, were imaged simultaneously below 40 mK.

Design of a self-aligned, wide temperature range (300 mK-300 K) atomic force microscope/magnetic force microscope with 10 nm magnetic force microscope resolution.

We describe the design of a wide temperature range (300 mK-300 K) atomic force microscope/magnetic force microscope with a self-aligned fibre-cantilever mechanism. An alignment chip with alignment groves and a special mechanical design are used to eliminate tedious and time consuming fibre-cantilever alignment procedure for the entire temperature range. A low noise, Michelson fibre interferometer was integrated into the system for measuring deflection of the cantilever. The spectral noise density of the system was measured to be ∼12 fm/√Hz at 4.2 K at 3 mW incident optical power. Abrikosov vortices in BSCCO(2212) single crystal sample and a high density hard disk sample were imaged at 10 nm resolution to demonstrate the performance of the system.

Seroprevalence of hepatitis B and C viruses: awareness and safe practices of hairdressers in Izmir: a survey.

OBJECTIVES: The aim of the study is to determine the seroprevalence of hepatitis B (HBV) and hepatitis C virus (HCV) infection in barbers and to assess the awareness of these employees related to occupational risks of HBV and HCV. MATERIALS AND METHODS: In this study, 2145 barbers in Izmir were given an occupational safety seminar. Blood samples were collected from 2066 voluntary participants and 1284 individuals completed the questionnaires. Sera were tested for the presence of HBV and HCV markers by ELISA. RESULTS: Our results document low levels of knowledge about HBV and HCV infection, risk perception and adequate protection among participants before the seminar session. Of the participants, 63.5% reported that they had suffered from equipment-related injuries during the last month. The prevalence of HBsAg positive and anti-HCV individuals of the 2066 person was found to be 2.2% and 0.4%, respectively. CONCLUSIONS: Hairdressers' knowledge of HBV, HCV and health hazards associated with their profession was inadequate. The prevalence of HBsAg positive and anti-HCV was similar to that among the general population.

A Novel Label-Free Optical Biosensor Using Synthetic Oligonucleotides from E. coli O157:H7: Elementary Sensitivity Tests.

SiO(2)-TiO(2) thin films for use as fiber optic guiding layers of optical DNA biosensors were fabricated by the sol-gel dip coating technique. The chemical structure and the surface morphology of the films were characterized before immobilization. Single probe DNA strands were immobilized on the surface and the porosity of the films before the hybridization process was measured. Refractive index values of the films were measured using a Metricon 2010 prism coupler. On the surface of each film, 12 different spots were taken for measurement and calculation of the mean refractive index values with their standard deviations. The increased refractive index values after the immobilization of single DNA strands indicated that immobilization was successfully achieved. A further refractive index increase after the hybridization with target single DNA strands showed the possibility of detection of the E. coli O157:H7 EDL933 species using strands of 20-mers (5'-TAATATCGGTTGCGGAGGTG -3') sequence.

An outbreak of gastroenteritis associated with intestinal parasites.

Intestinal protozoa are one of the leading causes of waterborne outbreaks. Stool samples of 196 residents from a village of Izmir, using the public water supply, were collected during an outbreak of gastroenteritis. Patients were asked to fill out a questionnaire reporting on gender, age, gastrointestinal symptoms, whether or not there was a toilet in the house, their hygiene practices, and similar symptoms in the household members. Of the patients who had gastrointestinal symptoms (74.5%), diarrhea was observed in 69.5% whereas bloody and mucoid stools were observed in 20.4 %. The stool samples were examined for intestinal parasites by wet mount and trichrome stain and were also cultured in the Robinson medium. Pathogenic parasites were detected in 11 samples (5.6%) as follows: Giardia intestinalis in 7, Hymenolepis nana in 1 and Blastocystis hominis in 4. Entamoeba histolytica/dispar was not detected by direct wet mount in any of 8 patients who had E. histolytica/E. dispar in culture whereas it was detected in the trichrome stained slides of 3 patients. Amoeba prevalence in the 15-44 age-group was significantly high when compared with the 0-14 age group. The prevalence of pathogenic parasites was high among the people who had a toilet outdoors. Drinking water was thought to be a principal source of this outbreak.

The relationship between obesity and health related quality of life of women in a Turkish city with a high prevalence of obesity.

The purpose of this study was to demonstrate the relationship between body weight and HRQOL in a representative sample of nonpregnant women in reproductive age period. The data of this cross-sectional study was extracted from a survey: Manisa Demographic and Health Survey (MDHS) conducted in Manisa city in 2000. The study population of MDHS is a representative sample of 1602 reproductive (15-49) age women. World Health Organization Quality of Life Questionnaire abbreviated version (WHOQOL-BREF), which was composed of four domain factors (physical, psychological, social relations and the environment), was used to assess HRQOL. Each of four domains had a possible score ranged between 0 (poor HRQOL) and 20 (excellent HRQOL). The mean age of the women was 35.29+/- 8.19 years. Among them, 35.8 % had normal weight (BMI 18.5 to 24.9), 32.3 % were overweight (BMI 25.0 to 29.9) while 31.9 % were moderate and 3.4% were morbidly obese. After adjusting for age, level of education and co-morbid illnesses, subjects with a BMI higher than normal value, had significantly lower HRQOL scores, compared to normal-weight individuals on each of the domains, except for the environmental domain. Our results suggested that the body weight alone could negatively affect HRQOL. In other words, obesity not only increased the risk of morbidity and mortality, but also affected the perceived health and life quality negatively. In conclusion, in addition to age, socioeconomic status and co-morbid illnesses, body weight should also be controlled in studies examining HRQOL.

Solid or liquid? Solidification of a nanoconfined liquid under nonequilibrium conditions.

There has been a long-standing debate about the physical state and possible phase transformations of confined liquids. In this report, we show that a model-confined liquid can behave both as a Newtonian liquid with very little change in its dynamics and as a pseudosolid, depending solely on the rate of approach of the confining surfaces. Thus, the confined liquid does not exhibit any confinement-induced solidification in thermodynamic equilibrium. Instead, solidification is induced kinetically when the two confining surfaces are approached with a minimum critical rate. This critical rate is surprisingly slow (on the order of 6 A/s), explaining the frequent observation of confinement-induced solidification.

Contrasting children and women's health and the determinants of health in a small-sized city.

Contrasts that exist in urban infrastructure and accessibility of public health and social services between suburban and urban districts of mega-cities have been well defined. There has been less research in small-sized cities (population under 500,000). This cross-sectional study was done on 1,728 ever-married reproductive-aged women living in Manisa, Turkey, in the year 2000. The probability proportion to size cluster sampling approach was used in the sample selection. Data were collected for women and 7,016 inhabitants of the interviewed households. The data were collected from the women by face to face interviews. Suburban areas (illegally occupied public land called "Gecekondu" dwellings) in Manisa differ from other urban regions (legal settlements of the city) on socioeconomic factors including household occupancy, adult literacy, social class, rates of religious marriages, unemployment, health insurance coverage, migration, cultural segregation, and social status of women. Some traditional practices were also highly prevalent in gecekondu families, where poverty is more common. Although gross fertility rate (GFR), total fertility rate (TFR), and percent decrease of the TFR were higher for gecekondu women than urban women, total wanted fertility rate (TWFR) was lower. In urban neighborhoods, prevalence of contraceptive use was higher, and the infant and child mortality rates were lower; however, when rates were adjusted for mother's age, education and number of births, the differences turned out to be nonsignificant. Women living in urban areas receive better antenatal care, child immunization services, and professional health delivery assistance and services in a health facility; these services are very scarce in gecekondu districts. Health status of gecekondu populations can be improved by social and economic support and by making health services more available and accessible, especially maternity and child health services.