SILICON MONOXIDE
Introduction
Silicon monoxide, SiO, is an amorphous solid which does not have
a characteristic X-ray diffraction pattern. SiO is brown in powder
or pressed form and black in granular or lump form. It is stable
at room temperature, but at temperatures of 400-800°C, X-ray
readings show traces of the disproportionation products silicon
and quartz. SiO is a highly desirable coating material due to
its high deposition rate and ease of evaporation using low cost
resistance-heated coating systems. SiO is also noted for its
excellent environmental stability.
Applications
Optical
SiO coatings are used for optical applications in reflectors,
flood lamps, mirrors, jewelry, and other products. SiO coatings
can reduce reflection in the near infrared range or act as interference
layers. SiO is also ideal for use with ZnS and other materials
for reflective coatings. SiO layers formed in oxygen atmosphere
(Si203?) are used for antireflection coatings
or interference coatings for ray splitting in the visible range.
Electronic
SiO films are used in thin-film capacitors, hybrid circuits,
semiconductor components, and other electronic applications.
A variety of insulating and dielectric properties can be achieved
by proper selection of SiO film thickness.
Protective
SiO films are deposited on aluminum surface mirrors, lenses and
gratings to protect against corrosion and wear.
Experimental
New uses for SiO are being discovered on an ongoing basis. Consequently,
the demands for new forms or purities of SiO are also changing.
As one of the world's largest producers of fine and rare inorganic
materials, CERAC has the experience and manufacturing expertise
necessary to meet new challenges created by advancements in technology.
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Preparation
Silicon monoxide is generally prepared by condensing the vapor
formed when pure silicon and pure quartz are reacted in a vacuum
at high temperatures. The purity of the final SiO product is
determined by the starting materials and reaction procedures
used. Depending on the temperature of the collector, the finished
SiO will range from lightweight, brown-to-black porous pieces
to a dense, black glassy material.
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Purity
CERAC offers two grades of SiO: 99.9% and 99.99% metallic purity.
Both grades are ideal for vacuum deposition.
Typical Analysis
for
99.9% Pure SiO Pieces |
Typical Analysis
for
99.99% Pure SiO Pieces |
|
Fe 50-100 ppm |
Fe 1-20 ppm |
|
Al 100-200 ppm |
Cu 1-20 ppm |
|
Cu 20-50 ppm |
Ca 1-50 ppm |
|
Ti 20-30 ppm |
Mg 1-10 ppm |
|
Ca 10-100 ppm |
Al 1-50 ppm |
|
Mn 20-50 ppm |
Ti 1-20 ppm |
|
Ni 20-50 ppm |
Mn 1-20 ppm |
|
B 5-10 ppm |
|
|
Mg 20-50 ppm |
|
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Physical
Properties
|
Molecular Weight |
44.09 |
|
Melting Point |
Sublimes |
|
Crystal Structure |
Amorphous |
|
Solubility |
Insoluble in water. Soluble
in dilute hydrofluoric acid. |
|
Density |
2.13 to 2.18 g/cm3
(calculated) |
|
Bulk Density of Powder |
Approx. 0.9 g/cm3 |
|
Evaporation Temperature |
1100 to 1400°C |
|
Transparent Region |
0.45 to 7 microns |
Index
1.9
1.85
1.83
1.6 |
Wavelength (Microns)
0.05
1.0
4.0
7.0 |
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Evaporation
Parameters
SiO films are typically produced by evaporating at 2 x 10-6
Torr with substrate temperatures of 100 to 150°C. Resistance
heating in baffle boats is the most common evaporation method
used, but E-beam evaporation may also be used, particularly with
pellets. By changing the deposition rate or oxygen back pressure,
various stoichiometries of SixOy can be
produced. The optical properties of the deposited SixOy
range between those of SiO and SiO2.
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Silicon
Monoxide-Chromium Compositions
CERAC prepares fused SiO-Cr compositions in various formulations
for use in microminiature resistors. The production technique
prevents separation of the SiO and Cr during evaporation and
thus yields uniform films. CERAC also manufactures sputtering
targets, solid rods, or other desired shapes of SiO-Cr. Please
inquire with specific requirements for prompt assistance.
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Forms
and Sizes Available
|
Item No. |
Purity |
Description |
|
S-1065 |
99.99% |
3-6 mm pieces |
|
S-2004 |
99.9% |
6-15 mm pieces |
|
S-1063 |
99.9% |
3-6 mm pieces |
|
S-2005 |
99.9% |
2-4 mm pieces |
CERAC offers other particle sizes for evaporation as well
as sputtering targets. To view pricing on the items listed above,
please visit our on-line catalog
and look-up by item number or chemical name. If you require a
custom manufactured item, please contact our sales department
at 414-289-9800 or ceracsales@beminc.com
with your specific requirements. You can also fill out our quotation request form.
NOTE: Facts pertaining to properties and processing parameters
of SiO were derived from published literature sources. Although
this information is believed to be correct, CERAC does not guarantee
its accuracy.
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