Chemical Control of Surfaces: From Fundamental Understanding to Practical Application

2012 ◽  
Vol 195 ◽  
pp. 65-70
Author(s):  
Melissa A. Hines
Keyword(s):  
Atomic Scale ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Microelectronics Industry ◽  
Industrial Adoption ◽  
Detrimental Impact ◽  
Metallic Impurities ◽  
Acidic Hydrogen

In the early days of the microelectronics industry, it became clear that even trace contaminants could have detrimental impact on the electronic properties of fabricated devices. This realization led to the development of the so-called RCA clean for silicon surfaces [], which uses sequential baths in basic and acidic hydrogen peroxide solutions, now known as SCA-1 and SCA-2, to oxidize organic materials, remove particulates, and bind metallic impurities. The detailed characterization of this process as well as its simplicity and economic viability soon led to its widespread industrial adoption. Although the RCA clean includes an optional etch in dilute HF between the two cleaning solutions to remove the native oxide layer, the overall process results in an extremely clean but electronically defectiveoxide-terminatedand thus extremely hydrophilic silicon surface, which we now know is quite rough on an atomic scale [].

In Situ Spectroscopic Ellipsometry Study of the Oxide Etching and Surface Damaging Processes on Silicon Under Hydrogen Plasma

1999 ◽  
Vol 591 ◽  
Author(s):  
I.M. Vargas ◽  
J.Y. Manso ◽  
J.R. Guzmán ◽  
B.R. Weiner ◽  
G. Morell
Keyword(s):  
Spectroscopic Ellipsometry ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Surface Damage ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Si Substrates ◽  
Oxide Etching

ABSTRACTWe employed in situ ellipsometry in the monitoring of surface damage to monocrystalline silicon (Si) substrates under hydrogen plasma conditions. These measurements were complemented with spectroscopic ellipsometry and Raman spectroscopy, in order to characterize the surface conditions. It was found that heating the Si substrate to 700°C in the presence of molecular hydrogen produces etching of the native oxide layer, which is typically 10 Å thick. When the already hot and bare silicon surface is submitted to hydrogen plasma, it deteriorates very fast, becoming rough and full of voids. Modeling of the spectroscopic ellipsometry data was used to obtain a quantitative physical picture of the surface damage, in terms of roughness layer t ickness and void fraction. The results indicate that by the time a thin film starts to grow on these silicon surfaces, like in the chemical vapor deposition of diamond, the roughness produced by the hydrogen plasma has already determined to a large extent the rough nature of the film to be grown.

Characterization of HF Treated (100) Si Surfaces by Surface Charge Analysis (SCA)

1992 ◽  
Vol 259 ◽  
Author(s):  
Jon T. Fitch
Keyword(s):  
Electrical Properties ◽  
Surface Charge ◽  
Chemical Bonding ◽  
Oxide Thickness ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Charge Analysis ◽  
The Stability ◽  
Over Time

ABSTRACTSurface Charge Analysis (SCA), and ellipsometry have been used to study the stability over time of HF treated (100) silicon surfaces as a function of the post-HF rinse time. Using SCA, the electrical properties of the chemical terminating layer of these silicon surfaces were measured. The surfaces which remained native oxide free the longest (−10 hours) had very low Qox and Dit values on the order of 1.0 × 1011/cm2 and 5.0 × 1010 eV−lcm−2, respectively. A good correlation was found between Dit and the native oxide thickness measured by ellipsometry. This and other results are discussed in terms of the chemical bonding on the silicon surfaces.

Microanalysis of a thin native oxide layer on silicon surfaces by parallel EELS

1989 ◽  
Vol 47 ◽  
pp. 224-225
Author(s):  
M.J. Kim ◽  
R.W. Carpenter
Keyword(s):  
Thin Layer ◽  
Oxide Layer ◽  
Room Temperature ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Si Substrate ◽  
Analytical Electron ◽  
Electron Microscopes ◽  
Made In

It is known that a thin layer of so-called “native oxide” is formed immediately on clean silicon surfaces upon exposure to air at room temperature. The composition of native oxide, SiOx, is uncertain. Various experimental methods have yielded values less than 2 for x. Parallel energy loss spectrometers fitted to analytical electron microscopes with field emission sources provide sufficient spatial resolution (≤4nm) for direct quantitative analysis of native oxide films. In this note we report the first EELS analysis of native oxide on silicon.CZ Si {001} wafers, HF etched at room temperature and rinsed in doubly deionized water, were exposed to air until placed in an UHV chamber. A thin layer of Au wasthen deposited on Si surfaces, so that the native oxide layer was preserved between Si substrate and deposited Au film. Cross section TEM specimens were made in the usual way.

Nanoparticle-Decorated Surfaces for the Study of Cell-Protein-Substrate Interactions

2004 ◽  
Vol 845 ◽  
Author(s):  
Jake D. Ballard ◽  
Ludovico M. Dell'Acqua-Bellavitis ◽  
Rena Bizios ◽  
Richard W. Siegel
Keyword(s):  
Silica Nanoparticles ◽  
Surface Coverage ◽  
Silicon Oxide ◽  
Substrate Surface ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Cell Protein ◽  
Fabrication And Characterization ◽  
Nanoscale Features

ABSTRACTThe present study was motivated by the need for accurately-controlled and well-characterized novel biomaterial formulations for the study of cell-protein-material interactions. For this purpose, the current research has focused on the design, fabrication and characterization of model native oxide-coated silicon surfaces decorated with silica nanoparticles of select sizes, and has examined the adhesion of osteoblasts and fibroblasts on these nanoparticle-decorated surfaces. The results demonstrate the capability to deposit nanoparticles of select diameters and substrate surface coverage onto native silicon oxide-coated silicon, the firm attachment of these nanoparticles to the underlying native silicon oxide, and that nanoparticle size and coverage modulate adhesion of osteoblasts and fibroblasts to these substrates. The material formulations tested provide a well-controlled and well-characterized set of model substrates needed to study the effects of nanoscale features on the functions of cells that are critical to the clinical fate of implantable biomaterials.

Different theoretical approaches at optical characterization of randomly rough silicon surfaces covered with native oxide layers

2018 ◽  
Vol 50 (11) ◽  
pp. 1230-1233 ◽  
Author(s):  
Ivan Ohlídal ◽  
Jiří Vohánka ◽  
Jan Mistrík ◽  
Martin Čermák ◽  
Daniel Franta
Keyword(s):  
Optical Characterization ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Oxide Layers ◽  
Theoretical Approaches

Atomic layer deposition of tungsten disulphide solid lubricant thin films

2004 ◽  
Vol 19 (12) ◽  
pp. 3443-3446 ◽  
Author(s):  
T.W. Scharf ◽  
S.V. Prasad ◽  
T.M. Mayer ◽  
R.S. Goeke ◽  
M.T. Dugger
Keyword(s):  
Thin Films ◽  
Atomic Layer Deposition ◽  
Solid Lubricant ◽  
Atomic Layer ◽  
Nucleation And Growth ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Tungsten Disulphide ◽  
Layer Deposition

The synthesis and characterization of crystalline tungsten disulphide (WS2) solid lubricant thin films grown by atomic layer deposition (ALD) using WF6 and H2S gas precursors was studied. A new catalytic route was established to promote nucleation and growth of WS2 films on silicon surfaces with native oxide. Scanning electron microscopy with energy dispersive spectroscopy and Raman spectroscopy were used to determine the film morphology, composition, and crystallinity. The films exhibited solid lubricating behavior with a steady-state friction coefficient of 0.04 in a dry nitrogen environment.

TEM characterization of silicon epitaxial layer grown on Si-TaS2, eutectic composites

1991 ◽  
Vol 49 ◽  
pp. 802-803
Author(s):  
C.M. Sung ◽  
M. Levinson ◽  
M. Tabasky ◽  
K. Ostreicher ◽  
B.M. Ditchek
Keyword(s):  
Substrate Surface ◽  
Bulk Sample ◽  
Surface Cleaning ◽  
Native Oxide ◽  
Czochralski Growth ◽  
Ion Milling ◽  
Cross Sectional ◽  
Cleaning Methods ◽  
Field Emission Cathodes

Directionally solidified Si/TaSi2 eutectic composites for the development of electronic devices (e.g. photodiodes and field-emission cathodes) were made using a Czochralski growth technique. High quality epitaxial growth of silicon on the eutectic composite substrates requires a clean silicon substrate surface prior to the growth process. Hence a preepitaxial surface cleaning step is highly desirable. The purpose of this paper is to investigate the effect of surface cleaning methods on the epilayer/substrate interface and the characterization of silicon epilayers grown on Si/TaSi2 substrates by TEM.Wafers were cut normal to the <111> growth axis of the silicon matrix from an approximately 1 cm diameter Si/TaSi2 composite boule. Four pre-treatments were employed to remove native oxide and other contaminants: 1) No treatment, 2) HF only; 3) HC1 only; and 4) both HF and HCl. The cross-sectional specimens for TEM study were prepared by cutting the bulk sample into sheets perpendicular to the TaSi2 fiber axes. The material was then prepared in the usual manner to produce samples having a thickness of 10μm. The final step was ion milling in Ar+ until breakthrough occurred. The TEM samples were then analyzed at 120 keV using the Philips EM400T.

Atomic scale characterization of GaInN/GaN multiple quantum wells in V-shaped pits

2011 ◽  
Vol 98 (18) ◽  
pp. 181904 ◽  
Author(s):  
Shigetaka Tomiya ◽  
Yuya Kanitani ◽  
Shinji Tanaka ◽  
Tadakatsu Ohkubo ◽  
Kazuhiro Hono
Keyword(s):  
Quantum Wells ◽  
Atomic Scale ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Scale Characterization
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