SiO2/Si Interfaces Studied by Stm and Hrtem

1990 ◽  
Vol 183 ◽  
Author(s):  
Masaaki Niwa ◽  
Minoru Onoda ◽  
Hiroshi Iwasaki ◽  
Robert Sinclair
Keyword(s):  
Oxide Thickness ◽  
High Energy ◽  
Interface Roughness ◽  
Oxide Interface ◽  
Oxide Interfaces ◽  
Polysilicon Gate ◽  
High Energy Electrons ◽  
Stm Image ◽  
Mos Structures ◽  
Good Agreement

AbstractThe morphology of SiO2/Si interfaces in a semiconductor LOCOS active area grown by several oxidation conditions has been studied, to compare the roughness of the interfaces observed by STM and HRTEM in particular. Samples consisted of typical MOS structures with a polysilicon gate/SiO2/Si(100). Hydrogen terminated Si surfaces were prepared by means of HF dipping for STM observations. The interface roughness of a “dry” oxide observed by HRTEM was slightly larger than that of a “wet” oxide. Good agreement could be found between STM and HRTEM for the wet oxide interfaces. As for the dry oxide interface, it was more difficult to obtain a reproducible STM image than for the wet oxide interface, but the reverse was true for HRTEM. During the HRTEM, high energy electrons damage the sample and reduce the oxide thickness, especially in the wet oxide samples.

Effects of Arsenic Segregation and Electron Trapping on the Capacitance-Voltage Behavior of Polysilicon and Polycide Gates

1990 ◽  
Vol 182 ◽  
Author(s):  
J. Lin ◽  
S. Batra ◽  
K. Park ◽  
J. Lee ◽  
S. Banerjee ◽  
...  
Keyword(s):  
Oxide Thickness ◽  
Electron Trapping ◽  
Dopant Segregation ◽  
Polysilicon Gate ◽  
Gate Oxide Thickness ◽  
Capacitance Voltage ◽  
Higher Temperature ◽  
Amorphous Si ◽  
Mos Structures ◽  
Mos Device

AbstractThis paper discusses the effects of dopant segregation and electron trapping on the capacitance-voltage characteristics of arsenic-implanted polysilicon and amorphous Si gate MOS structures fabricated with and without a TiSi2 layer. The effects of gate bias, annealing temperature, silicide formation and polysilicon grain microstructure on the C-V characteristics have also been studied. The results show that insufficient arsenic redistribution at 800°C, coupled with carrier trapping at polysilicon grain boundaries and dopant segregation in TiSi2 causes depletion effects in the polysilicon gate and in turn, an anomalous capacitance-voltage behavior. The depletion tends to increase the “effective” gate oxide thickness and thereby degrade MOS device performance. Higher temperature anneals (≥ 900°C) are sufficient to achieve degenerate doping in the polysilicon gates and avoid the depletion effects.

Studies of Oxide Desorption From GaAs by Diffuse Electron Scatfering and Optical Reflectivity

1991 ◽  
Vol 222 ◽  
Author(s):  
T. Van Buuren ◽  
T. Tiedje ◽  
M. K. Weilmeier ◽  
K. M. Colbow ◽  
J. A. Mackenzie
Keyword(s):  
Oxygen Plasma ◽  
Oxide Thickness ◽  
High Energy ◽  
Secondary Electrons ◽  
Oxide Layers ◽  
Gaas Substrates ◽  
Pressure Oxygen ◽  
High Energy Electrons ◽  
Order Of Magnitude ◽  
Magnitude Increase

ABSTRACTWe have determined that the temperature for desorption of gallium oude from GaAs increases linearly with oxide thickness, for oxide layers between about 6Å and 26Å thick. Different thicknesses of oxide layers were created by varying the exposure time of the GaAs wafers to a low pressure oxygen plasma. In addition, we show by diffuse light scattering that highly polished GaAs substrates roughen during the oxide desorption. These results are interpreted in terms of a model in which the oxide evaporates inhomogeneously. The oxide desorption was also studied by monitoring the secondary electrons produced by the high energy electrons from the RHEED gun. After the gallium oxide desorption there is a reversible, order of magnitude, increase in the number of secondary electrons produced. We interpret this result as evidence for the formation of microscopic gallium droplets on the GaAs surface.

scholarly journals Study of Interface Charge Densities for ZrO2and HfO2Based Metal-Oxide-Semiconductor Devices

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
N. P. Maity ◽  
Reshmi Maity ◽  
R. K. Thapa ◽  
S. Baishya
Keyword(s):  
Metal Oxide ◽  
Oxide Thickness ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Charge Densities ◽  
Interface Charge ◽  
Capacitance Voltage ◽  
P Type ◽  
Mos Structures ◽  
Good Agreement

A thickness-dependent interfacial distribution of oxide charges for thin metal oxide semiconductor (MOS) structures using high-kmaterials ZrO2and HfO2has been methodically investigated. The interface charge densities are analyzed using capacitance-voltage (C-V) method and also conductance (G-V) method. It indicates that, by reducing the effective oxide thickness (EOT), the interface charge densities (Dit) increases linearly. For the same EOT,Dithas been found for the materials to be of the order of 1012 cm−2 eV−1and it is originated to be in good agreement with published fabrication results at p-type doping level of1×1017 cm−3. Numerical calculations and solutions are performed by MATLAB and device simulation is done by ATLAS.

The K -shell ionization of atoms by high-energy electrons

1958 ◽  
Vol 247 (1251) ◽  
pp. 550-556 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Born Approximation ◽  
Marked Improvement ◽  
Relativistic Effects ◽  
High Energy ◽  
High Energies ◽  
High Energy Electrons ◽  
Shell Ionization ◽  
Good Agreement

An expression for the cross-section for K -shell ionization of atoms by electrons is obtained by using Moller’s relativistic modification of the Born approximation. Results are presented for the elements with atomic numbers less than 30. For nickel the calculated cross-sections are in good agreement with those measured by Kirkpatrick and his collaborators, a marked improvement due to the allowance for relativistic effects being found at high energies of impact. The normalization of the wave function of the ejected electron is discussed in the appendix.

The Effect of Roughness Features on Mos Surface Electric Field and Fowler-Nordheim Tunneling Behavior

1997 ◽  
Vol 473 ◽  
Author(s):  
Heng-Chih Lin ◽  
Edwin C. Kan ◽  
Toshiaki Yamanaka ◽  
Simon J. Fang ◽  
Kwame N. Eason ◽  
...  
Keyword(s):  
Electric Field ◽  
Three Dimensional ◽  
Tunneling Current ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Interface Roughness ◽  
Normal Electric Field ◽  
Surface Electric Field ◽  
Tunneling Behavior ◽  
Nordheim Tunneling

ABSTRACTFor future CMOS GSI technology, Si/SiO2 interface micro-roughness becomes a non-negligible problem. Interface roughness causes fluctuations of the surface normal electric field, which, in turn, change the gate oxide Fowler-Nordheim tunneling behavior. In this research, we used a simple two-spheres model and a three-dimensional Laplace solver to simulate the electric field and the tunneling current in the oxide region. Our results show that both quantities are strong functions of roughness spatial wavelength, associated amplitude, and oxide thickness. We found that RMS roughness itself cannot fully characterize surface roughness and that roughness has a larger effect for thicker oxide in terms of surface electric field and tunneling behavior.

Experimental investigation and modelling of light scattering in a-Si:H solar cells deposited on glass/ZnO:Al substrates

2002 ◽  
Vol 715 ◽  
Author(s):  
J. Krc ◽  
M. Zeman ◽  
O. Kluth ◽  
F. Smole ◽  
M. Topic
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Solar Cells ◽  
Angular Distribution ◽  
Light Scattering ◽  
Optical Model ◽  
Distribution Functions ◽  
Interface Roughness ◽  
Scattering Parameters ◽  
Good Agreement

AbstractThe descriptive scattering parameters, haze and angular distribution functions of textured ZnO:Al transparent conductive oxides with different surface roughness are measured. An approach to determine the scattering parameters of all internal interfaces in p-i-n a-Si:H solar cells deposited on the glass/ZnO:Al substrates is presented. Using the determined scattering parameters as the input parameters of the optical model, a good agreement between the measured and simulated quantum efficiencies of the p-i-n a-Si:H solar cells with different interface roughness is achieved.

An Analytical Drain Current Model for Dual-material Gate Graded - channel and Dual-oxide Thickness Cylindrical Gate (DMG-GC-DOT) MOSFET

2019 ◽  
Vol 9 (2) ◽  
pp. 291-297
Author(s):  
Hind Jaafar ◽  
Abdellah Aouaj ◽  
Ahmed Bouziane ◽  
Benjamin Iñiguez
Keyword(s):  
Current Model ◽  
Drain Current ◽  
Oxide Thickness ◽  
Subthreshold Current ◽  
The Poisson Equation ◽  
Strong Inversion ◽  
Cylindrical Form ◽  
Silvaco Atlas ◽  
Dual Material ◽  
Good Agreement

Background: A novel Dual Material Gate Graded Channel and Dual Oxide Thickness Cylindrical Gate (DMG-GC-DOT) MOSFET is presented in this paper. Methods: Analytical model of drain current is developed using a quasi-two-dimensional cylindrical form of the Poisson equation and is expressed as a function of the surface potential, which is calculated using the expressions of the current density. Results: Comparison of the analytical results with 3D numerical simulations using Silvaco Atlas - TCAD software presents a good agreement from subthreshold to strong inversion regime and for different bias voltages. Conclusion: Two oxide thicknesses with different permittivity can effectively improve the subthreshold current of DMG-GC-DOT MOSFET.

scholarly journals Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

2019 ◽  
Vol 209 ◽  
pp. 01007
Author(s):  
Francesco Nozzoli
Keyword(s):  
Electron Flux ◽  
Space Station ◽  
Cosmic Ray ◽  
High Energy ◽  
Precision Measurements ◽  
High Energy Electrons ◽  
Electrons And Positrons ◽  
Positron Flux ◽  
Rigidity Dependence ◽  
Alpha Magnetic Spectrometer

Precision measurements by AMS of the fluxes of cosmic ray positrons, electrons, antiprotons, protons as well as their rations reveal several unexpected and intriguing features. The presented measurements extend the energy range of the previous observations with much increased precision. The new results show that the behavior of positron flux at around 300 GeV is consistent with a new source that produce equal amount of high energy electrons and positrons. In addition, in the absolute rigidity range 60–500 GV, the antiproton, proton, and positron fluxes are found to have nearly identical rigidity dependence and the electron flux exhibits different rigidity dependence.

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