Papers by Keyword: Silicon

Abstract: This paper is a comparison of the carrier deflection mechanism of a new magnetic sensor structure between the tunneling Field Effect Transistor (TFET) structure and the FinFET structures so-called MAG-TFET and MAG-FinFET.The device relies on carrier deflection from magnetically induced forces. The MAG-TFET current is caused by electron tunneling and drifting through the bulk under gate while the MAG-FinFET current is caused by the drift channel carrier from the inversion layer induced by gate voltages and there is also a bulk current beneath the substrate. The carrier deflection of the device is due to the current in the induced channel and current in the bulk. From the results, carrier deflection in the induced channel is better than in the bulk. The device sensitivity depends on the proportion of these two currents.

Abstract: Selective removal of silicon might open-up the possibility of reusing silicon-contaminated spent catalyst. Unfortunately, study regarding this topic is still scarce. The effect of important parameters such as leaching treatment time and temperature was investigated, and the process conditions were optimized using response surface methodology (RSM) based on central composite design (CCD). Based on analysis of variance (ANOVA) results, leaching treatment time was found to be the most significant parameter, followed by temperature. Higher temperature and longer treatment time were satisfactorily enough for efficient silicon leaching from spent catalyst. The obtained quadratic model (R² = 0.995) shows a good correlation between the predicted values and experimental data. The optimum condition for silicon leaching was identified to be a temperature of 213.3°C and a treatment time of 5.83 hours.

Abstract: In this work, ray tracing is used to investigate the effects of pyramid texture angle towards light absorption and photocurrent in 250 μm-thick crystalline silicon (c-Si) absorber. Upright pyramids with texture angles of 10-50^o are investigated. Planar c-Si absorber is used as a reference. When the pyramid angle increases, the broadband reflection reduces due to enhanced light scattering which leads to improved light absorption. At angle of 50^o, the weighted average reflection (WAR) reduces to 14.7% and broadband light absorption increases. The optical path length enhancement increases to 12 at wavelength of 1100 nm. The reflection and photogenerated current density (J_g) exhibit an inverse relationship with increasing zenith angle. With increasing zenith angle, the reflection from the c-Si absorber increases and this results in lower light absorption and J_g. In the passivated emitter rear cell (PERC) solar cell, the planar solar cell exhibits short-circuit current density (J_sc) of 26 mA/cm² with conversion efficiency of 13.6%. When both the pyramids and the silicon nitride (SiN_x) anti-reflective coating (ARC) are incorporated on the solar cell, the J_sc increases to 39 mA/cm² and conversion efficiency increases to 20.5%. This is attributed to the enhanced light-trapping and light-coupling effects in the device.

Abstract: This paper reports the temperature and the concentration dependence of anisotropic etching for (100) p-Silicon in an aqueous KOH solution etching rate of wet etching has been experimentally determined with varying concentrations and the temperature of the KOH solution. The texturing process was managed at different etching durations ( 20 min, 40 min, and 60 min). XRD test showed that the lowest value of grain size was 5.0 nm (obtained with the highest porosity percentage of 50% with 4.5% KOH concentration for 60 min). FESEM test showed that the pore diameter increased with increasing etching time. The lowest reflectance value was (2.8 % at 550 nm wavelengths for samples treated with 4.5% KOH concentration for 60 min etching time. The refractive index value was 1.8 for the same black Si sample, also Hall test is introduced.

Abstract: The DFT calculations were performed to study the structural, electronic and optical properties of Si. The open source computer code, Quantum ESPRESSO used is for first-principles electronic structure modeling based on density functional theory. The optimized crystal lattice constant, band gap, density of states (DOS) and band structure were calculated. The calculated value of lattice constant was in good agreement with reported value. The band gap was calculated using three different pseudo potentials. The HSE hybrid functional provided best agreement of band gap calculations with literature values. The pseudo-dielectric functions was also calculated to estimate the optical properties including refractive indices, extinction coefficients, reflectivities and absorption coefficients in the spectral energy ranges from 0 eV to 10 eV.

Abstract: This paper presents system performance indices for a class-B power amplifier using Double-Gate (DG) Metal Oxide Semiconductor Field Effect Transistor (MOSFET). It also presents a comparative analysis of three power amplifiers using different switching devices, i.e. Bipolar Junction Transistor (BJT), MOSFET, and DG MOSFET. The MOSFET used in this research work is based on Silicon for n-MOSFET and SiO₂ has been used as oxide layer. These power amplifiers are also being designed and simulated to test the speed and time (taken for each of these power amplifiers) to get the output signal when an input signal is applied. A comparison of these three power amplifier circuits is taken in the tabular form to conclude which power amplifier circuit performs better regarding its switching speed and the time. Switching speed relates with the time taken to amplify the signal, which is the same as its time to amplify the signal to a specific gain. Settling time for these three types of power amplifiers have also been tested and presented for the performance of these power amplifiers.

Abstract: The static and cyclic mechanical behavior of samples of composite material with a matrix made of silicone rubber or low-pressure polyethylene reinforced with fibers of titanium nickelide with a martensitic structure has been investigated. It is shown that such composite materials have high deformation cycle resistance.

Abstract: The study of the silicon crystallization mechanism by standard analytical methods is difficult since the temperature of liquid silicon in the ladle during oxidative refining is quite high rising to 1500-1600 °C. Therefore, the method of mathematical modelling was used. To understand the mechanism of inclusions formation in silicon the authors applied a method of computer-generated state diagrams of three-component systems using the soft package Diatris. The package allows one to study the behavior of components involved in various physical and chemical transformations, and the interaction of elements with each other during the crystallization of the silicon melt. This work studies the behavior of such impurities as Fe, Ti, B, and C. To achieve the set goals, the ternary diagrams were constructed and analyzed for the Si-Ti-Fe, Si-Ti-B, Si-Ti-C, Si-Fe-B, Si-Fe-C, and Si-B-C systems. To characterize the increase in the number of crystals when a multicomponent alloy passes the crystallization interval, the crystallization rate was calculated. It is established that the most probable impurity compounds in crystalline silicon are SiFe_0.4B_0.06, FeTiSi₅, SiB_0.06Ti_0.33, and SiTi_0.4C_0.1.

Abstract: This research work designs a power amplifier with the use of Silicon-based Double-Gate (DG) MOSFET. It is a novel device used to amplify the input signal of an audio signal, etc. This research paper provides information on the problem identification in the existing models and its design objectives with its design constraints. It also reduces crossover distortion due to DG MOSFET instead of BJTs and MOSFETs in the class-B power amplifier. This is a low-power device for the mA range using SiO₂ as a dielectric material.

Abstract: The Indium Gallium Arsenide (InGaAs) based MOSFETs have been widely used in the research of high-speed devices with higher frequency. It has some application in the designing areas of power amplifiers. The InGaAs mainly have greater electron mobility and the lesser band gap in their compound makes them more suitable for developing high-speed devices. The Indium Gallium Arsenide compound-based MOSFETs are designed using the source/drain grown on a passive layer of Indium Phosphide substrate. This helps in reducing the power budget of the MOSFET and thereby reduces source and drain resistance. The re-grown layers over the bulk have serious issues such as parasitic capacitance and greater electrical field at the terminals of the gate along with the drain terminal. This results in a larger leakage current along with the terminals and thereby induces the degradation of the frequency of the application amplifiers. The high-ƙ dielectric along the gate terminal makes the device immune to leakage current for lesser frequency applications. The optimum material for the dielectric may be Hafnium (IV) Oxide – HfO₂ which has been used as a sidewall in the proposed InGaAs MOSFET design. The device simulation was carried out in a way to evaluate the characteristics of the proposed designs. The results were submissive to the conventional MOSFETs in terms of output capacitance over the source and drain terminals, leakage current in the drain terminal, and improved frequency parameters. The results also suggested that the sidewall design over the gate terminal constitutes the frequency improvement without losing the power and current characteristics.