Optical Silicon Wafers

university wafer substrates

What Optical Grade Silicon Do You Need?

A scientist requested a quote for the following:

25mm, 25.4mm or similar Thickness: 1mm Si Wafer,
1-1-1, optical grade (intrinsic Rs>2000Ohm cm)

UniversityWafer, Inc. Quoted:

Pure Si wafers, 25.4mm (1") Dia, 100 orientation, Undoped Rs>2000Ohm cm, and DSP,optical grade, Thickness 300+/-25 um,Qty. 10pcs

Reference #267943 for pricing

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Optical Grade Silicon Transmission

A university researcher asked us to quote the following:

Optical Grade Silicon.
Orientation: Monocrystalline,
type: N and/or P.
Resistivity: N>1, P>10 Ohm.cm.
Transmission: >52% from 2.5-
5.0micron through polished 0.2"
Purity: >99.999%.
DIA: 101.60 +0.0/-0.127mm.
THK: 1.00 +0.050/-0.050mm.

Polish 2 sides.
Scratch/Dig: 40/20.
Flatness: NS.
Clear Aperture: 90% of part
Wedge/Etv: <0.0508.
Chips: <0.508.
Perpendicularity: <=0.002”

UniversityWafer, Inc. Quoted. Reference #212418 for pricing

For the Optical Silicon wafers, we also offer n-type wafers:
Item   Qty.   Description
EI79c. 260   Silicon wafers, per SEMI Prime, P/P 4"Ø×1,000±25µm,
n-type Si:P[100]±0.5°, Ro=(10-50)Ohmcm,
TTV<10µm, Bow<40µm, Warp<40µm,
Both-sides Epi Ready polished, SEMI Flats (two),
Sealed in Empak or equivalent cassette

Note: Above wafers meet your specifications including "Transmission >52% over wavelength range of 2.5 to 5.0µm"

Prime Grade and Optical Grade Silicon Wafers

Prime grade silicon wafers are the highest grades of silicon, produced from synthetic fused silica. Prime grade silicon wafers have smooth, arcuate, continuous taper regions and phonon absorption peaks. Prime grade silicon wafers are the most expensive and are used in the most advanced devices. For more information, read our article on optical grade silicon. Here's a step-by-step method to make them.

Synthetic fused silica produces optical grade silicon wafers

Synthetic fused silica is a synthetic material that has low metallic impurities and is transparent deeper into what is optical grade siliconthe ultraviolet spectrum than traditional crystalline silicon. One centimeter-thick optical grade silicon wafers have a 50% transmittance at 170 nm and a few percent at 160 nm. Their infrared transmission is limited by strong water absorptions.

This material is transparent to ultraviolet light, making it a good candidate for use in electronic devices. It is also one of the least porous materials used for computer chips. Its optical properties are superior to those of other optical materials. It has low thermal expansion coefficient and is transparent in the ultraviolet, visible and near-infrared regions. It is also an excellent substrate for projection masks.

The chemical reaction that produces highly purified silica is an example of a high-quality, amorphous material. In this process, silica tetrachloride (SiCl4) is burned in a hydrogen-oxygen flame. Oxygen and silicon combine to form a stable solid, and chlorine escapes as HCl. The resulting synthetic silica is very fine and often exhibits very little metallic impurities. This material also has a low-level of hydrogen, which makes it suitable for use in the manufacture of optical grade silicon wafers.

Prime grade silicon wafers are the highest grade of silicon

There are many types of silicon wafers, but Prime grade is the most expensive. This grade is also known as "device quality," as it has high polishing and negligible deviations from specifications. Prime grade silicon wafers are considered the best choice for semiconductor fabrication, photolithography, and particle monitors. But the price tag reflects the benefits of this grade. To find out whether you should buy a particular silicon wafer, read the following descriptions.

The epi layer will be polysilicon, with a characteristic oxide backseal of about three to five thousand atoms. The backseal prevents Boron outgassing and contamination of the n-doped front side. Prime grade silicon wafers will not emit gasses or elements even at a temperature of 1,000degC/1832degF.

The Miller Index defines the growth planes and directions of crystalline silicon. Each plane has a different arrangement of atoms and lattice. For example, a primary slice orientation is (100) while a secondary slice orientation is (111). These orientations are important because each slice is unique, and it affects the crystallography of the semiconductor. However, the Miller Index does not determine the optimum orientation for a particular device.

Optical grade silicon wafers have phonon absorption peaks

The frequency of phonon absorption peaks in optical grade silicon wafers varies as a function of temperature. During the onset of the phonon absorption, the frequency of the peaks shifts from low to high. The peak absorbance decreases with increasing temperature, indicating a decrease in bandgap width and an increase in phonon population. The first excitonic absorption peak overlaps with the phonon emission peak, and the broadening at the low energy end is gradual.

Optical grade silicon wafers exhibit strong angular functions. For example, the curves on the right are for bare silicon with a thin native oxide, and the curves on the left are for polysilicon on oxide (SiO2). Polysilicon on oxide (PSO) exhibits low emissivity at shallow angles, which would be unsuitable for pyrometer collection.

The transmission spectra of crystalline silicon wafers (Fig.1) and amorphous silicon films (Fig. 2) reveal no difference in the range of three to five um. However, all four types of optical grade silicon have phonon absorption peaks in the range of 6.5 to 25 um, and the OCz-Si has additional peaks at 5.8 um, 9.1 um, and 19.4 um.

Optical grade silicon wafers have a smooth, arcuate and continuous taper region

Optical grade silicon wafers are generally flat, with a continuous taper region. They are produced in two forms - monocrystalline and polycrystalline. The monocrystalline silicon is produced through a Czochralski crystal growth process, while the polycrystalline silicon is produced by a float zone method. CZ silicon is cheaper, but it has an oxygen induced absorption band at nine microns. This type of silicon has good transmission properties from 1.2 um to 7 um, with the added dopant phosphorus or boron. Regardless of the production process used, the silicon wafers meet SEMI standards.

The taper region 26 can be continuous, smooth, arcuate, or s-tapered. The evanescent tail of the light beam 32 only contacts the out-coupling medium 22 slightly, so the intensity of the output beam is small. The thickness of the optical grade silicon wafers may vary from 0.5 mm to 50 mm.

Optical grade silicon wafers have flat, continuous taper regions, which aid in chip orientation and type identification. These features are important for optical devices, such as cameras and LEDs. If they are flat and arcuate, the chip edges will be more stable, thus preventing chip loss. These features are the key to high-quality optical grade silicon.

They are used as an optical window

They are made of glass, but they also have many properties that make them inherently unsuitable for many applications. They exhibit some degree of optical reflection, which causes power loss and causes parasitic back-reflections, which irritate laser devices. Anti-reflection coatings are available for optical windows. Broadband coatings suppress reflections more effectively than narrowband ones. Some optical windows are uncoated, but users can also choose to custom-coat them.

Optical windows can be customized, including the shape, size, sacrificial coatings, and more. Customized windows should be selected according to their AOI and reflectivity over the wavelengths of interest. Some windows are made with a high degree of surface hardness, a measure of their resistance to damage by pressure differentials. Optical windows must have high surface quality to ensure accurate measurements.

Optical windows are flat, transparent substrates that transmit a certain portion of the electromagnetic spectrum. They are commonly used as protective barriers for sensitive sensors. Selecting the correct substrate material for the application is important, since different materials have different optical properties. For example, Alpine Research Optics manufactures Near-IR, visible, AR-coated, and UV windows. To order a custom-made optical window, contact a leading supplier of precision optics.

Optical grade silicon wafers have a high transparency in the ultraviolet spectral range

Optical grade silicon wafers with a high spectral translucency are a promising new material for semiconductor applications. These wafers exhibit excellent transparency in the ultraviolet range, making them ideal for use in solar cells and other photonic devices. In order to obtain these wafers, thermal oxidation is performed on a silicon substrate. The process involves the production of silicon dioxide, a transparent material with low polarizability, through a chemical reaction that causes the silicon to lose some of its original volume.

The transparency of optical grade silicon wafers in the ultraviolet spectral range depends on the optical pass of the radiation through the material. The thickness of the silicon wafers is a key parameter that impacts its spectral translucency. For example, FZ-Si has an ultrahigh transmission compared to OCz-Si. As a result, FZ-Si is considered to be a better choice for the production of these optical devices.

UV-grade silica is a synthetic material manufactured by oxidizing pure silicon or fusing it with a flame. It is transparent to ultraviolet light and has no absorption bands in the visible spectrum. It also has excellent optical properties in the IR spectrum. However, it is often more expensive and less available than UV-grade silica. But UV-grade fused silica has high transparency in the ultraviolet spectral range.

They are used as a substrate for optical filters

The main materials used as substrates for optical filters are glass, plastics and crystalline materials. Glass is the most commonly used substrate material, but plastics can be easily processed and are also less expensive than glass. Glass is often used for optical filters because it has high impact resistance and is easy to machine. Plastics can also be used to make beam splitters over wide wavelength ranges. Some plastic materials may be used for these filters, but they are not as durable as glass.

Optical glass is the most common substrate material for optical filters. Absorption glass is the most common type of optical glass. Other common glass substrate materials include HB850 and CB535. Colorless optical glass K9 and float glass are also commonly used. Fused quartz is another popular substrate material. Glass substrates should be selected carefully to meet specific requirements and have a good optical density range. Different substrate materials have different components and have different physical or chemical properties.

In addition to glass, carbon fibres are also common. These are used to create a substrate for optical filters. The resulting optical filters can be as narrow as 1 micron. Several different kinds of carbon fibres can be used for constructing optical filters. These materials are made from glass, carbon fibre, and cellulose acetate. However, some plastics may have different properties. If you are looking for a specific type of substrate, you may want to research a few different materials and see which one is best suited for your needs.