Effect of Light Soaking on Hot Wire Deposited a-Si:H Films

1995 ◽  
Vol 377 ◽  
Author(s):  
Daewon Kwon ◽  
J. David Cohen ◽  
Brent P. Nelson ◽  
Eugene Iwaniczko
Keyword(s):  
Physical Properties ◽  
Hydrogen Content ◽  
Defect Density ◽  
Hot Wire ◽  
Junction Capacitance ◽  
Capacitance Measurements ◽  
Hydrogen Level ◽  
Defect Densities ◽  
Effect Of Light ◽  
Good Agreement

ABSTRACTWe present the results of studies on the defect properties and the effect of light soaking for various hot wire deposited (HW) films. We employ junction capacitance measurements together with the transient photocapacitance spectroscopy to measure the deep defect densities in as-grown state (state A) and in light soaked state (state B). Good agreement is found between the defect densities measured from both measurements. The HW film with a hydrogen content of 10 – 12 at.% shows physical characteristics and defect densities similar to conventional PECVD films. The HW films with hydrogen content, CH, in the range 2 – 9 at.% show a smaller defect density in state B than the defect density of the film with higher CH. However, the film with a hydrogen level of less than 1 at.% exhibits markedly inferior physical properties.

Capacitance and Transient Photocapacitance Studies of Tetrahedral Amorphous Carbon

2000 ◽  
Vol 621 ◽  
Author(s):  
Kimon C. Palinginis ◽  
A. Ilie ◽  
W.I. Milne ◽  
J. David Cohen
Keyword(s):  
Amorphous Carbon ◽  
Urbach Energy ◽  
Defect Density ◽  
Intrinsic Property ◽  
Band Tail ◽  
Junction Capacitance ◽  
Tetrahedral Amorphous Carbon ◽  
Thermally Activated ◽  
A Value ◽  
Defect Densities

ABSTRACTWe have applied junction capacitance and transient photocapacitance measurements to undoped tetrahedral amorphous carbon (ta-C)/silicon carbide (SiC) heterostructures to deduce defect densities and defect distributions in ta-C. The junction capacitance measurements show two thermally activated processes. One can be related to the activation of carriers out of defects at the ta-C/SiC interface while the other one with an activation energy of 0.36eV is an intrinsic property of the ta-C. The defect density at the ta-C/SiC interface is estimated to be roughly 9 ± 2 × 109 cm−2. The transient photocapacitance measurements have allowed us to observe the broader band tail of ta-C, giving a value (Urbach energy) of 230meV.

Low Hydrogen Content, High Quality Hydrogenated Amorphous Silicon Grown by Hot-Wire CVD

1999 ◽  
Vol 557 ◽  
Author(s):  
Brent P. Nelson ◽  
Richard S. Crandall ◽  
Eugene Iwaniczko ◽  
A. H. Mahan ◽  
Qi Wang ◽  
...  
Keyword(s):  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Hydrogen Content ◽  
Defect Density ◽  
Flow Direction ◽  
Scale Up ◽  
Hydrogenated Amorphous Silicon ◽  
Hot Wire ◽  
High Quality ◽  
Hydrogenated Amorphous

AbstractWe grow hydrogenated amorphous silicon (a-Si:H) by Hot-Wire Chemical Vapor Deposition (HWCVD). Our early work with this technique has shown that we can grow a-Si:H that is different from typical a-Si:H materials. Specifically, we demonstrated the ability to grow a-Si:H of exceptional quality with very low hydrogen (H) contents (0.01 to 4 at. %). The deposition chambers in which this early work was done have two limitations: they hold only small-area substrates and they are incompatible with a load-lock. In our efforts to scale up to larger area chambers—that have load-lock compatibility—we encountered difficulty in growing high-quality films that also have a low H content. Substrate temperature has a direct effect on the H content of HWCVD grown a-Si:H. We found that making dramatic changes to the other deposition process parameters—at fixed substrate temperature and filament-to-substrate spacing—did not have much effect on the H content of the resulting films in our new chambers. However, these changes did have profound effects on film quality. We can grow high-quality a-Si:H in the new larger area chambers at 4 at. % H. For example, the lowest known stabilized defect density of a-Si:H is approximately 2 × 1016 cm-3, which we have grown in our new chamber at 18 Å/s. Making changes to our original chamber—making it more like our new reactor—did not increase the hydrogen content at a fixed substrate temperature and filament-to-substrate spacing. We continued to grow high quality films with low H content in spite of these changes. An interesting, and very useful, result of these experiments is that the orientation of the filament with respect to silane flow direction had no influence on film quality or the H content of the films. The condition of the filament is much more important to growing quality films than the geometry of the chamber due to tungsten-silicide formation on the filament.

Pseudo Transistor Matrix for Defect Density Extraction of Gate Oxide Shorts

2011 ◽  
Vol 378-379 ◽  
pp. 767-771
Author(s):  
Yong Ding ◽  
Xiao Hua Luo ◽  
Cao Gao
Keyword(s):  
Defect Density ◽  
Critical Factor ◽  
Gate Oxide ◽  
Test Vehicle ◽  
Manufacture Process ◽  
Testing Data ◽  
Testing Cost ◽  
Conventional Test ◽  
Defect Densities ◽  
Good Agreement

Gate oxide shorts (GOS) defect is a critical factor in influencing yield or reliability of the wafer. Due to the conventional test vehicles are not appropriate to collect mass of testing data for GOS defect densities detection and have different manufacture process from the normal transistors resulting in the high testing cost. In this paper, a novel pseudo transistor matrix (PTM) is proposed for GOS density extraction which has almost the same structure as normal transistor. By assuming that GOS are completely independent, the defect density of GOS is extracted from the layout attributes and yield with PTM as a test vehicle to collect mass of testing data. Experimental results show that the extracted GOS defect density is in a good agreement with inline e-test data.

Vulcanization of Elastomers. 23. The Chemical Kinetics of Vulcanization Reactions and The Physical Properties of The Vulcanizates. I

1960 ◽  
Vol 33 (2) ◽  
pp. 335-341
Author(s):  
Walter Scheele ◽  
Karl-Heinz Hillmer
Keyword(s):  
Activation Energy ◽  
Physical Properties ◽  
Chemical Kinetics ◽  
Kcal Mole ◽  
First Order ◽  
Equilibrium Swelling ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization ◽  
Limiting Value ◽  
Good Agreement

Abstract As a complement to earlier investigations, and in order to examine more closely the connection between the chemical kinetics and the changes with vulcanization time of the physical properties in the case of vulcanization reactions, we used thiuram vulcanizations as an example, and concerned ourselves with the dependence of stress values (moduli) at different degrees of elongation and different vulcanization temperatures. We found: 1. Stress values attain a limiting value, dependent on the degree of elongation, but independent of the vulcanization temperature at constant elongation. 2. The rise in stress values with the vulcanization time is characterized by an initial delay, which, however, is practically nonexistent at higher temperatures. 3. The kinetics of the increase in stress values with vulcanization time are both qualitatively and quantitatively in accord with the dependence of the reciprocal equilibrium swelling on the vulcanization time; both processes, after a retardation, go according to the first order law and at the same rate. 4. From the temperature dependence of the rate constants of reciprocal equilibrium swelling, as well as of the increase in stress, an activation energy of 22 kcal/mole can be calculated, in good agreement with the activation energy of dithiocarbamate formation in thiuram vulcanizations.

Solitons propagation dynamics in a saturable PT-symmetric fractional medium

2021 ◽  
Author(s):  
Davood Hajitaghi Tehrani ◽  
Mehdi Solaimani ◽  
Mahboubeh Ghalandari ◽  
Bahman Babayar Razlighi
Keyword(s):  
Monte Carlo ◽  
Numerical Methods ◽  
Physical Properties ◽  
Maximum Intensity ◽  
Step Method ◽  
Saturation Parameter ◽  
Potential Depth ◽  
Fractional System ◽  
Nonlinear Fractional Schrödinger Equation ◽  
Good Agreement

Abstract In the current research, the propagation of solitons in a saturable PT-symmetric fractional system is studied by solving nonlinear fractional Schrödinger equation. Three numerical methods are employed for this purpose, namely Monte Carlo based Euler-Lagrange variational schema, split-step method, and extrapolation approach. The results show good agreement and accuracy. The effect of different parameters such as potential depth, Levy indices, and saturation parameter, on the physical properties of the systems such as maximum intensity and soliton width oscillations are considered.

scholarly journals The Physical and Thermodynamic Functions of Borides

2017 ◽  
Vol 18 (1) ◽  
pp. 58-63
Author(s):  
N.Yu. Filonenko
Keyword(s):  
Free Energy ◽  
Physical Properties ◽  
Thermodynamic Functions ◽  
Point Of View ◽  
Energy Potential ◽  
High Temperature Expansion ◽  
Temperature Dependences ◽  
Function Calculation ◽  
First Time ◽  
Good Agreement

In the paper the physical properties and thermodynamic functions of borides Х2В (Х=W, Mo, Mn, Fe, Co, Ni та Cr) are studied with accounting for fluctuation processes. We use the microstructure analysis, the X-ray structural and the durometric analyses to determine the physical properties of alloys. In the paper it is determined the phase composition and physical properties of borides. In this paper for the first time it is determined the thermodynamic functions of borides using the Hillert and Staffansson model with accounting for the first degree approximation of high-temperature expansion for the free energy potential of binary alloys. We obtain the temperature dependences for such thermodynamic functions as Gibbs free energy, entropy, enthalpy and heat capacity Ср along with their values at the formation temperature for Х2В (Х=W, Mo, Mn, Fe, Co, Ni та Cr). The approach under consideration enables to give more thorough from the thermodynamic point of view description of borides formed from the liquid. The outcomes of the thermodynamic function calculation for borides are in good agreement with experimental data and results of other authors.

scholarly journals Improvement of CdS?CuxS Solar Cell Performance by CdS Etching under Illumination

1992 ◽  
Vol 45 (1) ◽  
pp. 99 ◽  
Author(s):  
AM Al-Dhafiri
Keyword(s):  
Solar Cell ◽  
Single Crystals ◽  
Spectral Response ◽  
Cell Performance ◽  
Optical Characteristics ◽  
Solar Cell Performance ◽  
Junction Capacitance ◽  
Capacitance Measurements ◽  
Mixture Phase ◽  
Etched Surface

The influence of dark and light etching of CdS single crystals on the electrical and optical characteristics of the CdS-Cu",S heterojunction is investigated. It is shown through currentvoltage characteristics, spectral response and junction capacitance measurements that the junction of these cells is strongly affected by the presence of light during the etching process. It is found that when the CuS is formed on an etched CdS surface under light a chalcocite phase (CU2S) is obtained. In contrast, when the CuS layer is grown on a dark etched surface a mixture phase of chalcocite and djurleite (CUI� 96S) is found.

Fluctuating Temperature Measurements on a Heated Cylinder Placed in a Cylinder Near-Wake

2004 ◽  
Vol 126 (1) ◽  
pp. 62-69 ◽  
Author(s):  
Z. J. Wang ◽  
Y. Zhou ◽  
X. W. Wang ◽  
W. Jin
Keyword(s):  
Hot Wire ◽  
Heat Transfer Characteristics ◽  
Near Wake ◽  
Heated Cylinder ◽  
Fbg Sensor ◽  
Vortex Shedding Frequency ◽  
Sensor Measurement ◽  
Shedding Frequency ◽  
Good Agreement ◽  
Pronounced Peak

The local time-averaged temperature θs¯ and its fluctuating component θs on the surface of a heated circular cylinder immersed in a cylinder near-wake were measured using a fiber-optic Bragg grating (FBG) sensor. Three cylinder center-to-center spacing, i.e., L/d=5.20, 2.50, and 1.18, were investigated. In order to validate the FBG sensor measurement, a thermocouple and a single hot-wire were employed to measure θs¯ on the heated cylinder and streamwise fluctuating velocity u in the near-wake of the downstream cylinder, respectively. The FBG sensor measurement of θs¯ is in good agreement with that simultaneously obtained by the thermocouple. The measured θs is closely correlated to the hot-wire measurement; the θs-spectrum exhibits a pronounced peak at the vortex shedding frequency, as identified in Eu, for each L/d. The results suggest that the FBG sensor can be used to measure reliably both time-averaged and fluctuating temperatures. The heat transfer characteristics of the heated cylinder are examined for different L/d and further compared with the case of an isolated cylinder.

Growth and Characterization of 2″ 6H-Silicon Carbide

1999 ◽  
Vol 572 ◽  
Author(s):  
Erwin Schmitt ◽  
Robert Eckstein ◽  
Martin Kölbl ◽  
Amd-Dietrich Weber
Keyword(s):  
Silicon Carbide ◽  
Boundary Conditions ◽  
Growth Process ◽  
Defect Density ◽  
Crystal Quality ◽  
Process Conditions ◽  
Thermal Boundary Conditions ◽  
Sublimation Growth ◽  
Defect Densities

ABSTRACTFor the growth of 2″ 6H-SiC a sublimation growth process was developed. By different means of characterization crystal quality was evaluated. Higher defect densities, mainly in the periphery of the crystals were found to be correlated to unfavourable process conditions. Improvement of thermal boundary conditions lead to a decreased defect density and better homogeneity over the wafer area.

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