What is the difference between prime, test, and optical-grade raw wafers?

Prime wafers meet tight specifications on thickness uniformity, low defect density, and surface quality (e.g., single-side or double-side polished with low TTV and low particle counts) and are used for device fabrication. Test wafers are lower cost, often with relaxed flatness and defect specs, for process development or equipment calibration. Optical-grade wafers emphasize low bulk scattering, high transmittance over a target spectral band, and controlled birefringence, making them suitable as starting stock for lenses, windows, or waveplates.

What do terms like orientation, doping, and TTV mean for raw wafers?

Orientation specifies the crystallographic plane of the wafer surface (e.g., ⟨100⟩, ⟨111⟩, c-plane, a-plane), which affects etch rates, mechanical properties, and anisotropic optical behavior. Doping defines the intentional introduction of impurities (e.g., B, P, As in Si; Zn, S, Se in III–V) to control electrical conductivity and, in some crystals, optical absorption or nonlinear coefficients. TTV (Total Thickness Variation) quantifies the peak-to-valley thickness non-uniformity across the wafer and directly impacts epitaxy uniformity, polishing yield, and focus control in lithography.

Which key specifications should I evaluate when selecting raw wafers for photonic device fabrication?

Core parameters include material type, diameter, thickness, orientation, resistivity or carrier concentration, surface finish (single-side vs double-side polished, Ra), flatness (warp, bow), and TTV. For epitaxial or thin-film processes, low defect density, low particles, and tight thickness/flatness control are critical, while for high-power or IR optics you should prioritize absorption coefficient, inclusions, and internal stress of the bulk material.

How do I compare different wafer materials for optical and photonic applications?

Compare materials by spectral transmission range, refractive index and dispersion, thermal conductivity, coefficient of thermal expansion (CTE), hardness, and damage threshold. For example, Si wafers are opaque in the visible but suitable in the mid-IR and for electronics integration, sapphire offers wide transmission and high hardness, fused silica provides low thermal expansion and UV transparency, and III–V wafers (GaAs, InP) enable direct-bandgap optoelectronic devices but at higher cost and typically higher defect sensitivity.

What are typical lead times, customization options, and cost drivers for raw wafers?

Standard sizes and common orientations (e.g., 2–4 inch Si or sapphire, ⟨100⟩ or c-plane) are often available from stock or within 1–2 weeks, while custom diameters, off-cut angles, doping levels, or double-side super-polished surfaces may require 4–8 weeks depending on crystal growth and processing capacity. Pricing is mainly driven by material type, diameter, surface quality, flatness/TTV specs, doping complexity, and lot size, with small custom runs and stringent metrology requirements carrying noticeable premiums.

How can I find, compare, and request quotes for raw wafers on FindLight without creating an account?

On FindLight, navigate to Optics → Optical Materials → Raw Wafers and use the filters to narrow by material, diameter, thickness, orientation, and surface finish. You can open product pages side-by-side to compare specs such as TTV, flatness, and doping, then use the embedded contact or “Request Quote” form to send your requirements directly to suppliers without registration; responses are handled via the email address you provide.

Filter Products

Silicon (Si)

Raw Wafers for Optical and Light Transport Systems

4'' 6'' 8'' Silicon Wafer

Request Quote FAST RESPONSE

Sold by: Henan UM Optics Ltd Ships from: China

Specifications
Wafer Material:	Silicon (Si)
Diameter:	Not Specified
Thickness:	280 um
Size:	4'' 6'' 8''
Type:	NP

Did You Know?

Did you know that for high-end infrared optics, float-zone silicon raw wafers with resistivity >3 kΩ·cm are preferred because the extremely low dopant and oxygen content minimizes free-carrier absorption beyond ~5 µm? In many imaging and laser applications, the wafer’s orientation (e.g., ⟨100⟩ vs. ⟨111⟩) and total thickness variation (often specified

Related Resources

Frequently Asked Questions

Raw wafers are unprocessed or minimally processed substrate discs, usually 2–8 inches in diameter, sliced from single-crystal or polycrystalline ingots such as Si, GaAs, InP, sapphire, fused silica, or specialty optical crystals. They serve as starting materials for fabricating optical components, epitaxial structures, MEMS, and photonic integrated circuits through subsequent polishing, doping, deposition, lithography, and dicing steps.

Raw Wafers for Optical Material Processing

Raw Wafers in this category are unpatterned, substrate-grade optical disks used as starting materials for light transport, imaging, and photonic components. These Raw Wafers are typically sliced and polished from bulk optical materials, then further processed into lenses, windows, couplers, or integrated photonic structures.

Typical Specifications of Raw Wafers

Raw Wafers on FindLight cover common optical materials such as fused silica, BK7 and other crown glasses, sapphire, and semiconductor substrates. Buyers can expect key parameters such as:

Diameter: Common sizes range from 25.4 mm (1 inch) to 100 mm or larger, specified in mm or inches with tight tolerances.
Thickness: From sub-millimeter to several millimeters, often with ±0.05 mm or better tolerance.
Surface quality: Scratch-dig values (e.g., 20-10, 40-20) for optical-grade Raw Wafers, or basic lapped surfaces for further polishing.
Flatness and parallelism: λ/4 to λ/10 flatness over the clear aperture and parallelism down to a few arcseconds, depending on application.
Material grade: Optical transmission range, homogeneity, refractive index tolerance, and inclusion/bubble class.

For light transport applications, Raw Wafers are often selected for low absorption and scattering at the design wavelength, mechanical robustness, and compatibility with subsequent coating or bonding processes.

Use Cases for Light Transport and Photonics

Typical uses of Raw Wafers include substrate blanks for planar waveguides, beam splitters, mode-matching plates, coupling windows, and protective covers in high-power laser delivery systems. In R&D, Raw Wafers are also used as test plates for polishing processes and as base substrates for thin-film interference coatings.

Buyer Guidance on FindLight

When sourcing Raw Wafers, compare material type, optical transmission band, diameter, thickness, and surface specifications against your light transport design requirements. Verify thermal expansion and mechanical properties if wafers will be bonded, thinned, or exposed to elevated power densities. On FindLight you can review detailed datasheets, then contact suppliers directly to request quotes for specific Raw Wafers, custom diameters, or tighter tolerances. No registration is required to send inquiries, enabling rapid comparison of technical offers and lead times across vendors.