Optical Effects Induced by the Multilayer Nature of SOI Films During Transient Thermal Processing with a Radiant Line Heat Source.

1990 ◽  
Vol 201 ◽  
Author(s):  
Peter Y. Wong ◽  
Ioannis N. Miaoulis ◽  
P. Zavracky
Keyword(s):  
Heat Source ◽  
Radiation Effects ◽  
Silicon Oxide ◽  
Silicon Film ◽  
Radiation Heat Transfer ◽  
Linear Increase ◽  
Maximum Temperature ◽  
Line Heat Source ◽  
Silicon Oxide Layer ◽  
Optical Effects

AbstractRadiation heat transfer has been found to have the greatest Impact on the quality of the thin recrystalllzed silicon film during zone-melting recrystallizatlon (ZMR) processing. This study focused on the radiation effects during ZMR with an Infrared radiant line heat source such as a graphite strip heater. The multilayer nature of the capped sllicon-on-tnsulator (SOI) structure Induces complex optical effects which affect the temperature distribution during processing. A two dimensional numerical model of the ZMR process has been developed using a finite difference scheme. The effect of the radiant line heat source’s emission into the wafer has been modeled with a matrix method using Fresnel coefficients. A numerical parametric study was conducted to observe the effects of varying the thickness of the different layers In a capped SOI wafer on the maximum temperature and melt width attained. Results indicate that the variation of either the capping or insulating silicon oxide layer causes significant fluctuations of the reflectivity and temperature profile of the film. Increasing the thickness of the Si layer results in a nearly linear increase in temperature and melt width after complete melting. Layering schemes that are sensitive to small variations In thickness that may result in large changes in reflectivity were Identified.

The Recrystallization Depth Control of the Excimer-Laser-Recrystallized Poly-Crystalline Silicon Film

1999 ◽  
Vol 557 ◽  
Author(s):  
Kee-Chan Park ◽  
Kwon-Young Choi ◽  
Jae-Hong Jeon ◽  
Min-Cheol Lee ◽  
Min-Koo Han
Keyword(s):  
Laser Beam ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Silicon Oxide ◽  
Crystalline Silicon ◽  
Silicon Film ◽  
Film Structure ◽  
Excimer Laser Annealing ◽  
Silicon Oxide Layer ◽  
Thin Oxide Film

AbstractA novel method to control the recrystallization depth of amorphous silicon (a-Si) film during the excimer laser annealing (ELA) is proposed in order to preserve a-Si that is useful for fabrication of poly-Si TFT with a-Si offset in the channel. A XeCl excimer laser beam is irradiated on a triple film structure of a-Si thin native silicon oxide (~20Å)/thick a-Si layer. Only the upper a-Si film is recrystallized by the laser beam irradiation, whereas the lower thick a-Si film remains amorphous because the thin native silicon oxide layer stops the grain growth of the poly-crystalline silicon (poly-Si). So that the thin oxide film sharply divides the upper poly-Si from the lower a-Si.

Conjugated Heat Transfer in a Laminar Boundary Layer With Heat Source at the Wall

1982 ◽  
Vol 104 (1) ◽  
pp. 90-95 ◽  
Author(s):  
A. Brosh ◽  
D. Degani ◽  
S. Zalmanovich
Keyword(s):  
Boundary Layer ◽  
Heat Conduction ◽  
Heat Source ◽  
Flow Direction ◽  
Boundary Layer Separation ◽  
Maximum Temperature ◽  
Maximum Temperature Difference ◽  
Line Heat Source ◽  
Solid Plate ◽  
Conjugated Heat Transfer

This work presents the solution of the temperature field in a two-dimensional laminar incompressible flow over a conducting solid plate with a line heat source located at the fluid-solid interface perpendicular to the flow direction. A numerical scheme was used to obtain the temperature profiles as a function of the source strength, and of the properties of the fluid and the solid. The heat conduction and forced convection in the fluid and the heat conduction in the solid were solved for the case of moderate temperature rise, where the assumption of constant properties applies. The model enables the improvement of an instrument for the detection of boundary layer separation. It was found that for the actual parameters of the separation detector, a distance of 4 to 24 mm between the sensors gives an indication of 70 percent of the maximum temperature difference.

Thermodynamic behaviour of microstretch viscoelastic solids with internal heat source

2014 ◽  
Vol 92 (5) ◽  
pp. 425-434 ◽  
Author(s):  
Sunita Deswal ◽  
Renu Yadav
Keyword(s):  
Heat Source ◽  
Normal Mode Analysis ◽  
Generalized Thermoelasticity ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Mode Analysis ◽  
Moving Heat Source ◽  
Line Heat Source ◽  
Epoxy Material ◽  
Mech Phys Solid

The dynamical interactions caused by a line heat source moving inside a homogeneous isotropic thermo-microstretch viscoelastic half space, whose surface is subjected to a thermal load, are investigated. The formulation is in the context of generalized thermoelasticity theories proposed by Lord and Shulman (J. Mech. Phys. Solid, 15, 299 (1967)) and Green and Lindsay (Thermoelasticity, J. Elasticity, 2, 1 (1972)). The surface is assumed to be traction free. The solutions in terms of displacement components, mechanical stresses, temperature, couple stress, and microstress distribution are procured by employing the normal mode analysis. The numerical estimates of the considered variables are obtained for an aluminium–epoxy material. The results obtained are demonstrated graphically to show the effect of moving heat source and viscosity on the displacement, stresses, and temperature distribution.

Effect of wet-chemical substrate smoothing on passivation of ultrathin-SiO2/n-Si(111) interfaces prepared with atomic oxygen at thermal impact energies

Open Physics ◽  
2011 ◽  
Vol 9 (6) ◽  
Author(s):  
Heike Angermann ◽  
Orman Gref ◽  
Bert Stegemann
Keyword(s):  
Atomic Oxygen ◽  
Silicon Oxide ◽  
Visible Region ◽  
Atomic Scale ◽  
Favourable Effect ◽  
Silicon Oxide Layer ◽  
Potential Applications ◽  
Wet Chemical ◽  
Pre Treatment ◽  
Impact Energies

AbstractUltrathin SiO2 layers for potential applications in nano-scale electronic and photovoltaic devises were prepared by exposure to thermalized atomic oxygen under UHV conditions. Wet-chemical substrate pretreatment, layer deposition and annealing processes were applied to improve the electronic Si/SiO2 interface properties. This favourable effect of optimized wet-chemical pre-treatment can be preserved during the subsequent oxidation. The corresponding atomic-scale analysis of the electronic interface states after substrate pre-treatment and the subsequent silicon oxide layer formation is performed by field-modulated surface photovoltage (SPV), atomic force microscopy (AFM) and spectroscopic ellipsometry in the ultraviolet and visible region (UV-VIS-SE).

The Effect of Inlet Turbulence Intensity on Nano-Particulate Soot Formation in Kerosene-Fueled Combustors

2016 ◽  
Author(s):  
Masoud Darbandi ◽  
Majid Ghafourizadeh
Keyword(s):  
Heat Transfer ◽  
Turbulence Intensity ◽  
Soot Formation ◽  
Mixture Fraction ◽  
Radiation Heat Transfer ◽  
Transport Equations ◽  
Maximum Temperature ◽  
Radiation Heat ◽  
Exhaust Gases ◽  
Soot Aerosol

In this work, we numerically study the effects of turbulence intensity at the fuel and oxidizer stream inlets on the soot aerosol nano-particles formation in a kerosene fuel-based combustor. In this regard, we study the turbulence intensity effects specifically on the thermal performance and nano-particulate soot aerosol emissions. To construct our computer model, we simulate the soot formation and oxidation using the Polycyclic Aromatic Hydrocarbons PAHs-inception and the hydroxyl concept, respectively. Additionally, the soot nucleation process is described using the phenyl route, in which the soot inception is described based on the formations of two-ringed and three-ringed aromatics from acetylene, benzene, and phenyl radical. We use the two-equation soot model in which the soot mass fraction and the soot number density transport equations are solved considering the evolutionary process of soot nanoparticles, where all the nucleation, coagulation, surface growth, and oxidation phenomena are suitable considered in calculations. For the combustion modeling part, we benefit from the flamelets library, i.e., a lookup table, considering a detailed chemical kinetic mechanism consisting of 121 species and 2613 elementary reactions and solve the transport equations for the mean mixture fraction and its variance. We take into account the turbulence-chemistry interaction using the presumed-shape probability density functions PDFs. We apply the two-equation high-Reynolds-number k-ε turbulence model with round-jet corrections and suitable wall functions in performing our turbulence modeling. Solving the transport equations of turbulence kinetic energy and its dissipation rate, the turbulence closure problem can be resolved suitably. Furthermore, we take into account the radiation heat transfer of soot and gases assuming optically-thin flame, in which the radiation heat transfer of the most important radiating species is determined locally through the emissions. To evaluate our numerical solutions, we first solve an available well-documented experimental test, which provides the details of a kerosene-fueled turbulent nonpremixed flame. Then, we compare the achieved flame structure, i.e., the distributions of mean mixture fraction, temperature, and soot volume fraction, with those measured in the experiment. Next, we change the turbulence intensities of the incoming fuel and oxidizer streams gradually. So, we become able to evaluate the effects of different turbulence intensities on the achieved temperature and soot aerosol concentrations. Our results show that using moderate turbulence intensities at both fuel and oxidizer stream inlets would effectively increase the maximum temperature inside the combustor and this would reduce the exhaust gases temperature. It also reduces the concentrations of soot in the combustor and its emission to the exhaust gases effectively.

Maxwell Fluids Unsteady Mixed Flow and Radiation Heat Transfer Over a Stretching Permeable Plate With Boundary Slip and Nonuniform Heat Source/Sink

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Liancun Zheng ◽  
Ning Liu ◽  
Xinxin Zhang
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Heat Source ◽  
Mixed Boundary ◽  
Radiation Heat Transfer ◽  
Radiation Heat ◽  
Boundary Slip ◽  
Analytical Approximations ◽  
Maxwell Fluids ◽  
Source Sink

This paper presents an analysis for the unsteady mixed boundary-layer flow and radiation heat transfer of generalized Maxwell fluids toward an unsteady stretching permeable surface in presence of boundary slip and nonuniform heat source/sink. The governing partial differential equations are converted into nonlinear ordinary differential equations and analytical approximations of solutions are derived by homotopy analysis method (HAM). The effects of the unsteadiness parameter, nonuniform heat source/sink parameter, suction/injection parameter, thermal radiation parameter and slip parameter on the fluid flow, and heat transfer characteristics are shown graphically and analyzed.

Effect of non-uniform heat source/sink on MHD boundary layer flow and melting heat transfer of Williamson nanofluid in porous medium

2019 ◽  
Vol 15 (2) ◽  
pp. 452-472 ◽  
Author(s):  
Jayarami Reddy Konda ◽  
Madhusudhana Reddy N.P. ◽  
Ramakrishna Konijeti ◽  
Abhishek Dasore
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Heat Source ◽  
Radiation Effects ◽  
Navier Stokes ◽  
Working Fluid ◽  
Content Type ◽  
Linear Ordinary Differential Equations ◽  
Uniform Heat ◽  
Source Sink

PurposeThe purpose of this paper is to examine the influence of magnetic field on Williamson nanofluid embedded in a porous medium in the presence of non-uniform heat source/sink, chemical reaction and thermal radiation effects.Design/methodology/approachThe governing physical problem is presented using the traditional Navier–Stokes theory. Consequential system of equations is transformed into a set of non-linear ordinary differential equations by means of scaling group of transformation, which are solved using the Runge–Kutta–Fehlberg method.FindingsThe working fluid is examined for several sundry parameters graphically and in a tabular form. It is noticed that with an increase in Eckert number, there is an increase in velocity and temperature along with a decrease in shear stress and heat transfer rate.Originality/valueA good agreement of the present results has been observed by comparing with the existing literature results.

Combined Conduction and Radiation Heat Transfer in Porous Materials Heated by Intense Solar Radiation

1985 ◽  
Vol 107 (1) ◽  
pp. 29-34 ◽  
Author(s):  
L. K. Matthews ◽  
R. Viskanta ◽  
F. P. Incropera
Keyword(s):  
Heat Transfer ◽  
Radiation Heat Transfer ◽  
Plane Layer ◽  
Single Scattering ◽  
Dominant Mode ◽  
Radiative Properties ◽  
Maximum Temperature ◽  
Transfer Model ◽  
Radiation Heat ◽  
Flux Approximation

An analysis is presented to predict the heat transfer characteristics of a plane layer of a semitransparent, high-temperature, porous material which is irradiated by an intense solar flux. A transient, combined conduction and radiation heat transfer model, which is based on a two-flux approximation for the radiation, is used to predict the temperature distribution and heat transfer in the material. Numerical results have been obtained using thermophysical and radiative properties of zirconia as a typical material. The results show that radiation is an important mode of heat transfer, even when the opacity of the material is large (τL > 100). Radiation is the dominant mode of heat transfer in the front third of the material and comparable to conduction toward the back. The semitransparency and high single scattering albedo of the zirconia combine to produce a maximum temperature in the interior of the material.

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