Open Access Original Research Article

Manufacturing and Electrical Characterization of MOS Devices of Ultrathin Silicon Dioxide Layer

Anis M. Saad

Physical Science International Journal, Page 1-11
DOI: 10.9734/PSIJ/2018/44368

Metal-Oxide-Semiconductor–MOS devices presented here with thermally grown oxide layer of 3.04-5.92 nm thick were fabricated using p-type Si substrate. Capacitance-voltage (C-V) and conductance-voltage (G/ω-V) characteristics in frequency range of 10 kHz-100 kHz between 22 and 100 °C were measured in darkness. Current-voltage (I-V) was measured at Troom in darkness. C-V and G/ω-V at various frequencies revealed the energy distribution of MOS interface states. Current transport mechanisms in the device were studied and the I-V was generally characterised by Fowler-Nordheim and direct tunnel mechanisms of current carriers transport. Interface state density, flat-band voltages and frequency dispersion were extracted from C-V measurements. The frequency dispersion indicates the presence of either interface traps or laterally inhomogeneous distribution of defect centres near Si/SiO2 interface. The concentration of charged defects and their location at Si/SiO2 interface were calculated from frequency characterization. Small densities of interface traps < 2×1011 eV-1 cm-2 show that SiO2-Si interface has reliable qualities and its oxide may find applications in CMOS as dielectric gates. C-V of sample of dox = 4.14 nm was used to calculate at (22, 30, 50, 75, 100°C) the capacitance in accumulation mode, interface charge density, flat band voltage, threshold voltage and density of interface traps (in minimum position), Dit,= 0.3×1011-1×1011 cm-2. G/ω-V characteristics at Troom for sample of dox = 4.14 nm at 10 kHz, 50 kHz and 100 kHz were obtained. C-V of all 4 samples at Troom was also used to calculate the mentioned oxide properties. Two samples of dox = 3.04 nm and 4.14 nm were studied using X-ray photoelectron spectroscopy technique and evaluation of Si 2p peak was obtained for dox = 3.04 nm. Exact SiO2 thickness for all samples was measured by an ellipsometer.

Open Access Original Research Article

Structural Properties of the Ferroelectric Nanocomposite (1-x) BaTiO3–(x) PbTiO3 Prepared by Tartrate Acid Method

A. Tawfik, D. M. Hemeda, M. Z. Said, M. M. Yousef

Physical Science International Journal, Page 1-17
DOI: 10.9734/PSIJ/2018/44797

BaTiO3 –PbTiO3 nanocomposite materials with the formula (1-x) BaTiO3–(x)PbTiO3 where x=0, 0.2, 0.4, 0.6, 0.8 and 1 were prepared using tartrate method .The structural properties of the samples were characterized using x-ray diffraction( XRD), Fourier Transformed Infrared (FTIR), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). All these structural properties were measured at room temperature.The average crystallite size ranges from 21.4 nm to 36.9 nm, the grain size estimated from SEM is between 71.9 nm to 80.9 nm.The average particle size estimated from TEM is between 22 nm to 82.7 nm, The FTIR spectra showed two vibration peaks, one around 559 cm -1 ѵ1 (stretching mode) and the other around 425 cm-1 ѵ 2 (bending mode).

Open Access Original Research Article

Temperature Extremes over Selected Stations in Nigeria

E. O. Eresanya, V. O. Ajayi, M. T. Daramola, R. Balogun

Physical Science International Journal, Page 1-10
DOI: 10.9734/PSIJ/2018/34637

This research aims to determine the temperature extremes for Ikeja (Lagos), Osogbo (Osun) and Maiduguri (Borno), Nigeria, West Africa using Statistica analytical tool. Thirty (30) years daily maximum and minimum temperature data for Lagos, Osogbo and Maiduguri used for this study were collected from Nigeria Meteorological Agency (NIMET), Oshodi, Nigeria. Analysis of extreme temperature trend indicated that in Ikeja the percentage occurrence of warm days (TX90P) in which the maximum temperature is above 34°C (90th percentile value) is increasing and the percentage occurrence of cold days (TX10P) in which the maximum temperature  is below 28°C [10thpercentile value] is decreasing, in Osogbo the percentage occurrence of warm days (TX90P) in which the maximum temperature is above 35°C [90th percentile value) is increasing at a slower rate whereas the percentage occurrence of cold days (TX10P, number of days) in which the maximum temperature is below 27°C [10th percentile value] is constant while in Maiduguri the percentage occurrence of warm days (TX90P, number of days) in which the maximum temperature is above 41°C [90th percentile value] is constant whereas the percentage occurrence of cold days (TX10P, number of days) in which the maximum temperature is below 30°C [10th percentile value]  is slightly increasing. Percentage of warm days indicate constant value at around 13-15% during the three (3) decades under investigation across the study areas while day time cooling increases slightly by 2% in Ikeja, 1% in Osogbo and 3% in Maiduguri significant level and Cold night decrease at 1% in Ikeja and remain constant in Osogbo but decrease by 5% in Maiduguri significant level.

Open Access Original Research Article

Ad Hoc Error Correction vs. Removal of Error’s Root

E. Comay

Physical Science International Journal, Page 1-8
DOI: 10.9734/PSIJ/2018/45286

An ad hoc correction of a theoretical error does not change other elements of the relevant theory. The mathematical structure of theoretical physics indicates that a removal of the root of an error has a much more profound meaning than that of just correcting an error. Herein, this general principle is applied to four physical issues: the standard derivation of the electromagnetic energy-momentum tensor; gauge transformations of the 4-potential of electromagnetic fields; the idea called the hadronic structure of the photon; the  factor that aims to project a quantum function into a parity violating form. The erroneous root of each of these issues is discussed and an appropriate line of research is suggested.

Open Access Original Research Article

Plasmas Computed with ATMED CR of the 4th Non Local Thermodynamic Equilibrium Code Comparison Workshop Database

A. J. Benita

Physical Science International Journal, Page 1-26
DOI: 10.9734/PSIJ/2018/44683

In this paper, there are presented some results calculated with code ATMED CR (ATom MEDium Collisional Radiative) of the 4th Non-LTE Code Comparison Workshop held in December 2005, when this software didn’t exist, having been released in 2017. NLTE population kinetics codes were tested of steady-state cases for C, Ar, Fe, Sn, Xe and Au plasmas selected for detailed comparisons. Apart from analysing dense plasma physics, the scope was expanded including the EUV lithography sources and photoionised plasmas.

The purpose of the paper is to present good results computed of ATMED CR of plasmas proposed in this scientific meeting of 2005. The results for plasma properties can be considered as relatively precise and optimal, being checked fundamentally the high sensitivity of calculations to changes in regions of local thermodynamic equilibrium (LTE) or non local thermodynamic equilibrium (NLTE), electronic and radiation temperatures, electronic density and plasma length. Frequency resolved and mean opacities are also displayed computed with ATMED CR using UTA (Unresolved Transition Array) formalism.