Fluorine-Silicon Reactions and the Etching of Crystalline Silicon

1988 ◽  
Vol 141 ◽  
Author(s):  
Chris G. Van De Walle ◽  
F. R. Mcfeely ◽  
S. T. Pantelides
Keyword(s):  
Density Functional ◽  
Semiconductor Device ◽  
Crystalline Silicon ◽  
State Of The Art ◽  
Density Functional Method ◽  
Surface Region ◽  
Functional Method ◽  
Device Fabrication ◽  
Near Surface ◽  
Comprehensive Picture

AbstractThe interaction between F atoms and crystalline Si, which is essential for etching processes in semiconductor device fabrication, is investigated with state-of-the-art theoretical techniques. The theory is based on the pseudopotential-density-functional method in a supercell geometry. A comprehensive picture of F reactions with the Si surface, the bulk, and the near-surface region is obtained, in terms of which the etching process is elucidated. Insertion of F into Si-Si bonds becomes possible because of relaxed steric constraints in the near-surface region. Dependence of the etch rate on doping follows naturally, in agreement with observations. Similarities and differences between F-Si and H-Si reactions are discussed.

Density-Functional Analysis on Vacancy Orbital and its Elastic Response of Silicon

2009 ◽  
Vol 1195 ◽  
Author(s):  
Takafumi Ogawa ◽  
Kenji Tsuruta ◽  
Hiroshi Iyetomi ◽  
Hiroshi Yamada Kaneta ◽  
Terutaka Goto
Keyword(s):  
Elastic Strain ◽  
Density Functional ◽  
Crystalline Silicon ◽  
Density Functional Method ◽  
Functional Method ◽  
Elastic Response ◽  
Boron Doped ◽  
Ultrasonic Measurements ◽  
Doped Silicon ◽  
Elastic Softening

AbstractRecent experiments on ultrasonic measurements of non-doped and boron-doped silicon indicate that vacancies in crystalline silicon can be detected through the elastic softening at low temperature. This is attributed to enhanced response of electronic quadrupole localized at the vacancies to the elastic strain. In the present work, the electronic quadrupole moment of the vacancy orbital in silicon and their strain susceptibility are evaluated quantitatively by using the density-functional method. We show the orbital of gap state is localized around vacancy but extended over several neighbors. The effect of applied magnetic field on the vacancy orbital and its multipole structures are also investigated. We find that the results obtained from these calculations are consistent with the ultrasonic experiments.

scholarly journals Interactions of Ruddlesden-Popper Phases and Migration-Induced Field-Stabilized Polar Phase in Strontium Titanate

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 693
Author(s):  
Christian Ludt ◽  
Elena Ovchinnikova ◽  
Anton Kulikov ◽  
Dmitri Novikov ◽  
Sibylle Gemming ◽  
...  
Keyword(s):  
Strontium Titanate ◽  
Density Functional ◽  
Surface Region ◽  
Point Of View ◽  
Polar Phase ◽  
Near Surface ◽  
Atomic Displacements ◽  
Induced Field ◽  
And Migration ◽  
Novel Concept

This work focuses on the validation of a possible connection of the known Ruddlesden-Popper (RP) phases and the novel concept of the migration-induced field-stabilized polar (MFP) phase. To study this subject, model structures of RP phases in bulk strontium titanate are analyzed by means of density functional theory (DFT). The obtained geometries are compared to experimental MFP data. Good agreement can be found concerning atomic displacements in the pm range and lattice strain inferred by the RP phases. Looking at the energy point of view, the defect structures are on the convex hull of the Gibb’s free energy. Although the dynamics to form the discussed defect models are not addressed in detail, the interplay and stability of the described defect model will add to the possible structure scenarios within the near-surface region of strontium titanate. As a result, it can be suggested that RP phases generally favor the MFP formation.

Computer Simulation of an Synthetic Ultraviolet Absorbent in the Interface of DMB and DMF

2010 ◽  
Vol 146-147 ◽  
pp. 966-971
Author(s):  
Qi Hua Jiang ◽  
Hai Dong Zhang ◽  
Bin Xiang ◽  
Hai Yun He ◽  
Ping Deng
Keyword(s):  
Computer Simulation ◽  
Computer Simulations ◽  
Density Functional ◽  
Density Functional Method ◽  
Mean Field ◽  
Functional Method ◽  
Dynamic Density ◽  
Interface Phase ◽  
Simulation Results

This work studies the aggregation of an synthetic ultraviolet absorbent, named 2-hydroxy-4-perfluoroheptanoate-benzophenone (HPFHBP), in the interface between two solvents which can not completely dissolve each other. The aggregation is studied by computer simulations based on a dynamic density functional method and mean-field interactions, which are implemented in the MesoDyn module and Blend module of Material Studios. The simulation results show that the synthetic ultraviolet absorbent diffuse to the interface phase and the concentration in the interface phase is greater than it in the solvents phase.

A New Approach for Calculating the Band Gap of Semiconductors within the Density Functional Method

2015 ◽  
Vol 242 ◽  
pp. 434-439 ◽  
Author(s):  
Vasilii E. Gusakov
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
Localized States ◽  
Experimental Accuracy ◽  
Functional Theory ◽  
New Approach ◽  
The Density Functional Theory

Within the framework of the density functional theory, the method was developed to calculate the band gap of semiconductors. We have evaluated the band gap for a number of monoatomic and diatomic semiconductors (Sn, Ge, Si, SiC, GaN, C, BN, AlN). The method gives the band gap of almost experimental accuracy. An important point is the fact that the developed method can be used to calculate both localized states (energy deep levels of defects in crystal), and electronic properties of nanostructures.

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