Si (optical grade) FZ-HR
Grade
FZ-HR = fZ high-resistivity
Pick for 8–14 µm thermal imaging, FTIR and THz optics where the CZ 9 µm oxygen band and free-carrier absorption must be eliminated.
Values for the FZ-HR condition
Other Si (optical grade) tempers and conditions
Si (optical grade) is listed in 3 conditions; see the grade overview at Si (optical grade).
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
CZ-100Default CZ | Default, lowest-cost optical silicon for 3–5 µm windows and lenses; interstitial oxygen gives a 9 µm absorption band, so it is less ideal for 8–12 µm. | — | 124 | 0 | 1,100 HV | 149 W/m·K |
FZ-HRThis page FZ high-resistivity | Pick for 8–14 µm thermal imaging, FTIR and THz optics where the CZ 9 µm oxygen band and free-carrier absorption must be eliminated. | — | 124 | 0 | 1,100 HV | 156 W/m·K |
CZ | Choose when maximum stiffness / cleavage-plane control is wanted, e.g. thin membranes, X-ray or diffractive elements. | — | 130 | 0 | 1,150 HV | 149 W/m·K |
What is Si (optical grade) FZ-HR?
Si (optical grade) FZ-HR is Si (optical grade) in the FZ-HR grade — pick for 8–14 µm thermal imaging, FTIR and THz optics where the CZ 9 µm oxygen band and free-carrier absorption must be eliminated. Si (optical grade) FZ-HR has a tensile strength of 124 MPa (18 ksi), stronger than 85% of glass grades. Elongation at break is 0% and the elastic modulus is 130 GPa (18.9 Msi). Si (optical grade) FZ-HR has a density of 2.33 g/cm³ (0.0841 lb/in³), lighter than 81% of glass grades. It melts at 1,414°C (2,577 °F). CZ-100 is the default condition FabDigit quotes; FZ-HR is available on request or by drawing note.
Advantages
- Conducts heat well — 156 W/m·K (90.1 BTU/hr·ft·°F), better than 98% of glass grades
- Stiff — 130 GPa (18.9 Msi), better than 88% of glass grades
- Lightweight — 2.33 g/cm³ (0.0841 lb/in³), better than 81% of glass grades
- Tough — resists crack growth — 0.9 MPa·√m (0.819 ksi·√in), better than 79% of glass grades
Limitations
- High embodied carbon — 120 kg CO₂/kg, worse than 94% of glass grades
- Limited service temperature — 250°C (482 °F), worse than 83% of glass grades
Si (optical grade) FZ-HR properties
Typical room-temperature values for Si (optical grade) FZ-HR; 15 are specific to this condition. Other listed values are Si (optical grade) reference data and may not represent this condition. Bars are the position among glass grades.
Physical5
Si (optical grade) FZ-HR has a density of 2.33 g/cm³ (0.0841 lb/in³), lighter than 81% of glass grades. It melts at 1,414°C (2,577 °F).
Mechanical12
Si (optical grade) FZ-HR has a tensile strength of 124 MPa (18 ksi), stronger than 85% of glass grades. Elongation at break is 0% and the elastic modulus is 130 GPa (18.9 Msi).
Thermal5
Si (optical grade) FZ-HR is rated for continuous service to 250°C (482 °F). It conducts heat at 156 W/m·K (90.1 BTU/hr·ft·°F), better than 98% of glass grades. Thermal expansion is 2.6 µm/m·K (1.44 µin/in·°F).
Electrical5
Si (optical grade) FZ-HR is an electrical insulator with a dielectric strength of 30 kV/mm (762 V/mil) and a resistivity of 100 Ω·m.
Chemical & Environmental2
Corrosion resistance is very good (80/100), better than 58% of glass grades.
Sustainability4
Producing a kilogram of Si (optical grade) FZ-HR takes about 2,000 MJ of energy and emits 120 kg of CO₂ — more than 97% of glass grades. Typical recycled content is 2%.
Manufacturability2
Si (optical grade) FZ-HR's machinability is poor (20/100, better than 56% of glass grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Si (optical grade) FZ-HR
Is Si (optical grade) easy to machine?
Diamond wire saw or ID saw for slicing, then diamond grinding/lapping; conventional cutting tools fail — SPDT is possible only with special tooling and gives limited tool life.
Can Si (optical grade) be welded?
Not weldable; join by optical contacting, silicon direct/fusion bonding, anodic bonding to glass, or low-stress epoxy/solder mounting.
Can Si (optical grade) be formed, bent or molded?
No plastic forming — parts are grown from the melt and generated to shape; aspheres and diffractive surfaces are ground or diamond-turned, deep features by KOH/DRIE etching.
What surface finishes work on Si (optical grade)?
Polish to <1 nm Rq and λ/10 flatness; almost always AR-coated (e.g. DLC or ZnS/YF3 stacks) because uncoated Fresnel losses cap transmission near 54%.
Si (optical grade) chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Ointerstitial oxygen ~10–20 ppma in CZ (9 µm absorption); <0.5 ppma in FZ | 0 | 8×10⁻⁴ |
| Csubstitutional carbon, <1 ppma typical | 0 – 5×10⁻⁴ | 1×10⁻⁴ |
| Bp-type dopant, set to reach target resistivity | ≈ 5×10⁻⁷ | 5×10⁻⁷ |
| Pn-type dopant, set to reach target resistivity | ≈ 5×10⁻⁷ | 5×10⁻⁷ |
| Sielectronic/optical purity, metallic impurities typically <1 ppba | ≥ 100 (balance) | — |
Si (optical grade) FZ-HR — frequently asked
What is Si (optical grade) FZ-HR used for?
Si (optical grade) FZ-HR is typically used for thermal imaging lenses, IR windows, beamsplitters and laser optics substrates. In short: lightweight LWIR lens material; high thermal conductivity window; always AR-coated.
What is the tensile strength of Si (optical grade) FZ-HR?
Si (optical grade) FZ-HR has a typical tensile strength of 124 MPa (18 ksi) — stronger than 85% of glass grades. Strength varies by condition: see the 3 listed tempers.
Is Si (optical grade) FZ-HR easy to machine?
Not especially — machinability is rated poor (20/100, better than 56% of glass grades). Diamond wire saw or ID saw for slicing, then diamond grinding/lapping; conventional cutting tools fail — SPDT is possible only with special tooling and gives limited tool life.
Can Si (optical grade) FZ-HR be welded?
Not weldable; join by optical contacting, silicon direct/fusion bonding, anodic bonding to glass, or low-stress epoxy/solder mounting.
What surface finishes work on Si (optical grade) FZ-HR?
Polish to <1 nm Rq and λ/10 flatness; almost always AR-coated (e.g. DLC or ZnS/YF3 stacks) because uncoated Fresnel losses cap transmission near 54%.
Can Si (optical grade) FZ-HR be formed, bent or molded?
No plastic forming — parts are grown from the melt and generated to shape; aspheres and diffractive surfaces are ground or diamond-turned, deep features by KOH/DRIE etching.
What is the maximum service temperature of Si (optical grade) FZ-HR?
Si (optical grade) FZ-HR is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Handbook of Optical Constants of Solids (silicon chapter) — Academic Press / Palik (1998)
- Silicon (Si) optical material data sheet — Crystran Ltd (2023)
- What is the Young's Modulus of Silicon? — Journal of Microelectromechanical Systems (Hopcroft, Nix, Kenny) (2010)
- SEMI MF84 — Test Method for Measuring Resistivity of Silicon Wafers — SEMI (2017)
- ASTM F1188 / ASTM F1391 — interstitial oxygen and substitutional carbon in silicon by IR — ASTM (2019)
- CRC Handbook of Chemistry and Physics, physical constants of silicon — CRC Press (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.