scholarly journals A Self-Consistent Model for Thermal Oxidation of Silicon at Low Oxide Thickness

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Gerald Gerlach ◽  
Karl Maser
Keyword(s):  
Thermal Oxidation ◽  
Silicon Oxide ◽  
Surface Concentration ◽  
Oxide Thickness ◽  
Oxidation Time ◽  
Fickian Diffusion ◽  
Oxide Surface ◽  
Microelectronic Fabrication ◽  
Consistent Model ◽  
Self Consistent

Thermal oxidation of silicon belongs to the most decisive steps in microelectronic fabrication because it allows creating electrically insulating areas which enclose electrically conductive devices and device areas, respectively. Deal and Grove developed the first model (DG-model) for the thermal oxidation of silicon describing the oxide thickness versus oxidation time relationship with very good agreement for oxide thicknesses of more than 23 nm. Their approach named as general relationship is the basis of many similar investigations. However, measurement results show that the DG-model does not apply to very thin oxides in the range of a few nm. Additionally, it is inherently not self-consistent. The aim of this paper is to develop a self-consistent model that is based on the continuity equation instead of Fick’s law as the DG-model is. As literature data show, the relationship between silicon oxide thickness and oxidation time is governed—down to oxide thicknesses of just a few nm—by a power-of-time law. Given by the time-independent surface concentration of oxidants at the oxide surface, Fickian diffusion seems to be neglectable for oxidant migration. The oxidant flux has been revealed to be carried by non-Fickian flux processes depending on sites being able to lodge dopants (oxidants), the so-called DOCC-sites, as well as on the dopant jump rate.

A Comparison of Tunneling Through Thin Oxide Layers on Step-free and Normal Si Surfaces

2002 ◽  
Vol 747 ◽  
Author(s):  
Antonio C. Oliver ◽  
Jack M. Blakely
Keyword(s):  
Thermal Oxidation ◽  
Oxide Thickness ◽  
Oxide Semiconductor ◽  
Electrical Performance ◽  
Oxide Surface ◽  
Interface Morphology ◽  
Device Structure ◽  
Atomic Steps ◽  
Surface And Interface ◽  
Step Density

ABSTRACTSurface and interface morphology may play an important role in the electrical performance of metal-oxide-semiconductor (MOS) devices with small characteristic dimensions. In previous work we showed how steps on the silicon surface influence the Si-SiO2 interface morphology and the outer oxide surface morphology following thermal oxidation [1]. The Si-SiO2 interface morphology is largely determined by the starting silicon substrate step distribution and atomic steps at the Si surface cause an inherent variation in oxide thickness after thermal oxidation. In the present study we report how roughness caused by increased interfacial step density may affect the electronic tunneling characteristics of an MOS device structure. To determine the extent to which the step morphology plays a role in the tunneling behavior of such devices, similar arrays of capacitors were fabricated on both Si surfaces with reduced step density and surfaces which had not undergone any special surface step removal treatment. The leakage currents due to tunneling for the two types of capacitors were measured and compared. Atomic steps cause an effective decrease in oxide thickness in those capacitors without reduced step density and this leads to increased leakage current.

scholarly journals Thermal oxidation improvement in semiconductor wafer fabrication

2019 ◽  
Vol 10 (3) ◽  
pp. 1141
Author(s):  
Christopher Julian Mahandran ◽  
Abdul Yasser Abd Fatah ◽  
Nurul Aini Bani ◽  
Hazilah Mad Kaidi ◽  
Mohd Nabil Bin Muhtazaruddin ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Flow Rate ◽  
Gas Flow ◽  
Elevated Temperatures ◽  
Oxide Thickness ◽  
Oxidation Time ◽  
Low Flow ◽  
Gas Flow Rate ◽  
Semiconductor Wafer ◽  
Location Factor

Thermal oxidation is a process done to grow a layer of oxide on the surface of a silicon wafer at elevated temperatures to form silicon dioxide. Usually, it en- counters instability in oxide growth and results in variation in the oxide thickness formed.  This leads to downtime of furnace and wafer scrap.  This study focuses on the factors leading to this phenomenon and finding the optimum settings of these factors. The factors that cause instability to oxide thickness were narrowed down to location of wafer in furnace, oxidation time, gas flow rate and temperature. Characterization and optimization were done using Design of Experiments. Full factorial design was implemented using 4 factors and 2 levels, resulting in 16 runs. Data analysis was done using Multiple Regression Analysis in JMP software. Actual versus predicted plot is examined to determine whether the model fit is significant. Adjusted <em>R</em><sup>2</sup> value was obtained at 99.8% or 0.998 indicating that there is very minimal variation of the data not explained by the model and thus confirming that the model is good. From the effect test, the factors were narrowed down from 4 factors to 3 factors. Location factor was found to have no impact. Significant factors that have impact are gas flow rate, oxidation time and temperature. Analyzing the leverage plots and least square mean plots, temperature was found to have the highest impact on oxide thickness. The model was further analyzed using prediction profiler in JMP to find the optimum settings for thermal oxidation process to meet the target oxide thickness of 8000A. Optimum setting for temperature was found to be at 958 C, gas flow rate at low flow rate (H<sub>2</sub>:6.5 slm and O<sub>2</sub>:4.5 slm), oxidation time at 280 min and location of wafers at both zone 1 and zone 2.

THEORY AND SELF-CONSISTENT MODEL OF DUST-DRIVEN WINDS

2002 ◽  
Vol 5 ◽  
pp. 65-65
Author(s):  
S. Liberatore ◽  
J.-P.J. Lafon ◽  
N. Berruyer
Keyword(s):  
Consistent Model ◽  
Self Consistent

scholarly journals Stellar Flares: Observations and Theory

1989 ◽  
Vol 104 (2) ◽  
pp. 49-52
Author(s):  
Suzanne L. Hawley
Keyword(s):  
Scaling Law ◽  
Dynamic Scaling ◽  
X Ray ◽  
Temperature Distributions ◽  
Photometric And Spectroscopic Observations ◽  
Stellar Flares ◽  
Consistent Model ◽  
Self Consistent ◽  
Flare Model ◽  
Large Flare

AbstractPhotometric and spectroscopic observations of a very large flare on AD Leo are presented. A self consistent model of a flare corona, transition region and chromosphere is developed; in particular the chromospheric temperature distributions resulting from X-ray and EUV irradiation by coronae of various temperatures are determined. The predicted line fluxes in Hγ are compared to the observed line fluxes to find the coronal temperature as a function of time during the flare. This run of temperature with time is then compared with the predictions of an independent theoretical flare model based on a dynamic scaling law (see paper by Fisher and Hawley, these proceedings).

scholarly journals A Self‐Consistent Model for Sorption and Transport in Polyimide‐Derived Carbon Molecular Sieve Gas Separation Membranes

2020 ◽  
Vol 132 (46) ◽  
pp. 20523-20527
Author(s):  
Oishi Sanyal ◽  
Samuel S. Hays ◽  
Nicholas E. León ◽  
Yoseph A. Guta ◽  
Arun K. Itta ◽  
...  
Keyword(s):  
Gas Separation ◽  
Molecular Sieve ◽  
Carbon Molecular Sieve ◽  
Separation Membranes ◽  
Gas Separation Membranes ◽  
Consistent Model ◽  
Self Consistent

scholarly journals The Rules for the Lattice Rotation Accompanying Slip as Derived From a Self-Consistent Model

1999 ◽  
Vol 31 (4) ◽  
pp. 217-230 ◽  
Author(s):  
R. A. Lebensohn ◽  
T. Leffers
Keyword(s):  
Solid Mechanics ◽  
Grain Shape ◽  
Rolling Plane ◽  
Lattice Rotation ◽  
Consistent Model ◽  
Plane Strain Deformation ◽  
Self Consistent ◽  
The One ◽  
Equiaxed Grains ◽  
Very High

The rules for the lattice rotation during rolling (plane strain) deformation of fcc polycrystals are studied with a viscoplastic self-consistent model. Very high values of the ratesensitivity exponent are used in order to establish Sachs-type conditions with large local deviations from the macroscopic strain. The lattice rotation depends on the grain shape. For equiaxed grains the lattice rotation follows the MA rule, which is the one normally used in solid mechanics. For elongated and flat grains the lattice rotation follows a different rule, the PSA rule. In the standard version the model performs a transition from MA to PSA with increasing strain. There is avery clear difference between the textures resulting from the two different rules. MA leads to a copper-type texture, and PSA leads to a brass-type texture.

scholarly journals Self-consistent model for ambipolar tunnelling in quantum-well systems

1995 ◽  
Vol 10 (5) ◽  
pp. 577-585 ◽  
Author(s):  
C Presilla ◽  
V Emiliani ◽  
A Frova
Keyword(s):  
Quantum Well ◽  
Consistent Model ◽  
Self Consistent
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