Crystal growth
Cimcoop has achieved a high level of vertical integration that allows us to control the entire production process from Silicon crystal growth to polished substrates that find multiple application in transmissive infrared optics and CO2 lasers.
Our seasoned team of engineers has over 3 decades of combined crystal growing experience. This allows us to produce high-purity (more than 99.999% pure) Czochralski-grown silicon with a very consistent quality. Our engineers understand the important interplay of optical transmission and resistivity and how to adapt them to suit each customer’s specific needs.
Physical properties of Silicon
| Melting Point | 1414°C |
| Density | 2.329 g/cm3 |
| Thermal Expansion Coefficient | 2.6 x 10-6/K |
| Youngs Modulus | <111> 187 GPa |
Transmission curve (Optical grade Silicon, uncoated)
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Specifications
| Diameter | Up to 152 mm (6”) |
| Grade | Optical |
| Purity | >99.999% |
| Transmission from 2.5 to 5 μm (optical grade) | >52% |
| Orientation Monocrystalline | <100> & <111>, polycrystalline |
Resistivity
(standard Optical grade) | > 20 Ohm.cm (P-type)
> 10 Ohm.cm (N-type) |
| Type (dopant) | P - type (Boron)
N - type (Phosphorus) |
| Refractive index (4 μm at 25 ℃) | 3.4289 and doesn’t vary more than 20 ppm over the entire blank |
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Plano blanks
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Our core product, the custom made as-cut plano Silicon blank, is used as a substrate for the production of IR lenses and windows operating in the 2 to 5 micron (MWIR) range. Plano silicon blanks come in round, rectangular and other complex shapes. We welcome requests for any quantity from prototype orders to thousands of pieces.
Plano Silicon blank specifications
| Diameter | Up to 152 mm (6”) |
| Thickness | 0.5 mm to 500 mm |
| Rectangles & Squares | up to 152 mm (6”) long |
Tolerances
| Diameter | - 0.03 mm |
| Thickness | ± 0.02 mm |
| Flatness | ≤10 μm |
| Parallelism | ≤ 20 μm |
| Perpendicularity | ≤ 20 μm |
| Chamfer | 0.1 to 1 mm |
| ETV | ≤ 20 μm |
| Roundness | ≤ 20 μm |
| Length & Width | ± 0.1 mm |
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Spherical blanks
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We offer pre-generated optical grade Silicon blanks of up to 152 mm (6”) in diameter.
Having Cimcoop generate your spherical curves can save you valuable production time and improve your cost efficiency.
We also offer fine ground surfaces that are ready for direct polishing.
Spherical Silicon blank tolerances
| Diameter | -0.05 mm |
| Thickness | ±0.05 mm |
| Flatness | ≤ 0.5% R |
| Chamfer | 0.1 to 1mm |
| ETV | ≤ 50 μm |
| Roundness | ≤ 20 μm |
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Polished plano blanks
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Cimcoop has in-house polishing capability allowing us to deliver polished Silicon windows of various shapes.
Conventional single spindle polishers as well as double-side polishing equipment allows us to polish Silicon substrates with very high surface quality.
Surface quality
| flatness | λ |
| S/D | 60/40 |
| Irregularity | λ/2 |
| Parallelism | 0.01 mm |
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