Specialty Graphites for the Photovoltaic Industry

GRAPhITE MATERIALS AnD SySTEMS

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Specialty Graphite and Process Solutions – made by SGL Group.

Advanced material, equipment, and process solutions

Engineered for customers from more than 35 industries

Tailor-made from the most comprehensive product portfolio

In-depth production and material knowledge

Consistent high quality, performance, and service

Attractive total cost of ownership

Broad Base. Best Solutions.

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Advanced solutions enable our customers to get ahead.SGL Group offers advanced solutions – even for challenging applications. We understand the specific requirements of our customers and combine in-depth production, material, and engineering knowledge with the most comprehensive specialty graphite portfolio. This makes us the partner of choice to leading companies in many different industries.

Exceptional resistance to heat and corrosion, high purity and mechanical strength are just a few of the outstanding properties which our materials offer. Specialty graphite products from SGL Group achieve optimal results where other materials fail. No matter what your specific requirements might be, we will identify the best solution from the most comprehensive range of specialty graphites.

Fine grain graphite: isostatic, vibration- molded, die-molded, extruded

Expanded natural graphite Carbon fiber-reinforced carbon (C/C) Soft and rigid graphite felts Silicon carbide-coated graphite materials

Additionally we use other materials like PTFE, silicon carbide, and specialty metals.

With our portfolio and technical know-how spanning more than 35 different industries, we engineer tailor-made solutions in close partnership with our customers.

SGL Group covers the entire value chain of specialty graphite production, including raw material processing, semi-finished product manufacture, precision machining, purification, and coating. When it comes to engineering of equipment and process solutions our service range makes the difference: We offer mechanical and process design, production, assembly, commis-sioning, and service – all from a one-stop shop.

This is how we control and ensure the consistent high quality, reliability, and performance of our products – and enable our customers to become more competitive. Challenge us. We are there for you worldwide.

Specialty graphite solutions for the photovoltaic industry

Photovoltaic producers and plant manufacturers ensure the energy supply of tomorrow. We have been involved in the solar industry from the outset and know its requirements. With innovative specialty graphite solutions, we are a partner of choice to leading companies.b Machining a meander heater

BUSInESS UnIT GRAPhITE MATERIALS AnD SySTEMS

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Metallurgical siliconValue chain Trichlorosilane (TCS)

Amorphous carbonMaterials made ofcarbon and graphite

Extruded, vibration-molded, isostatic graphites

Carbon electrodesProducts of theSGL Group

HCl synthesis units Heating elementsHeat shieldsInsulationVesselsElectrodes (polychucks)

Polysilicon

SIGRAFINE®extruded, vibration-molded, isostatic graphites SIGRAFINE® SiC Coating SIGRATHERM® carbon and graphite feltsSIGRABOND® carbon fiber-reinforced carbons and graphites�+�

More information at www.sglgroup.com/carbonelectrodes

�+�More information at www.sglgroup.com/processsolutions

Converter Siemens reactor

Specialty graphites – made by SGL Group.Solutions for the photovoltaic industry.

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In the Silicon-based PV value chain, specialty graphites are in-dispensable. This is because some applications operate at very high temperatures and in an extremely corrosive environ-ment: at the same time, high purity and precision are required.

For the challenging processes of the photovoltaic industry, we offer efficient solutions with specialty graphites. Our portfolio starts with electrodes for deposition of high-purity polysilicon. We also supply heaters, crucibles, and insulation components suitable for a variety of crystal growing units

CruciblesHeatersHeat shieldsInsulation

Slicing beamsCarrier boatsWafer carriers

SIGRAFINE®extruded, vibration-molded, isostatic graphitesSIGRATHERM® carbon and graphite feltsSIGRABOND® carbon fiber-reinforced carbons and graphites SIGRAFINE® SiC Coating

Growing silicon crystals Wafer

SIGRAFINE®isostatic graphites SIGRAFINE® SiC Coating SIGRABOND® carbon fiber-reinforced carbons and graphites

and processes, such as the Czochralski pulling process for the production of single silicon crystals and the DSS/VGF block casting process for multi-crystalline silicon. Our range is com-pleted by carrier systems for antireflective coating of solar wafers in PECVD units. Our components are normally manu-factured to individual requirements. In addition, we assist our customers in planning, design, and operational optimization.

SPECIALTy GRAPhITE SOLUTIOnS FOR ThE PhOTOVOLTAIC InDUSTRy

�+�SIGRAFINE® is the new brand name for our fine -grain  graphites, previously known under the names RINGSDORFF®, SIGRAFORM®, SIGRAMENT® and CRYSTA-SIL®.

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Products for the photovoltaic industryAs a reliable supplier and partner to our customers, we offer optimum solutions and process reliability for every application. What differentiates us:

Most comprehensive selection of high-purity specialty graphites

Consistently high material and product quality

Long-standing experience and material know-how

Individualized production tailored exactly to customer requirements

Application-specific finishing by cleaning, mechanical processing or coating

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Specialty graphites for polysilicon production

c Electrodes (polychucks) for Siemens reactors

b Meander heater for CZ units

c Graphite rigid felt cylinder for insulation of converters

Application-specific specialty graphites for polysilicon production

Applications ProductsGraphite

Soft felt Rigid felt C/C SiC coatedisostatic extruded vibration-

molded Fluidized-bed reactors (FBR) Reactors   ○Siemens CVD process Polychucks ○ ○

Converters (STC-TCS)

Gas distributors ○ ○ ○Heating elements ○ ○ ○ ○

Heat shields ○ ○ ○ ○Insulating cylinders ○

SPECIALTy GRAPhITES FOR ThE PhOTOVOLTAIC InDUSTRy

In Siemens reactors and STC-TCS converters for recycling process gases, temperatures up to 1000 °C (1800 °F) and a highly corrosive environment prevail. Our graphite components perform impressively well here because they are extremely resistant to heat and corrosion.

For many years now, we have been supplying polysilicon manufacturers with a range of plant components.These include purified electrodes for polysilicon deposition, heaters, gas ducts for STC-TCS converters, heat shields and thermal insulation components.

Our experts select the best materials for the specific require-ments and operating conditions and manufacture tailored products from them. With our newly developed shaping and connecting solutions, for example, we can supply converter insulation in virtually any length and diameter. To increase the service life of highly stressed components – like those in converters – we offer special silicon carbide (SiC) coatings.

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c Graphite components for CZ units

Crystal pulling by the Czochralski process (CZ) makes high demands on plant components. In addition to heat resistance and a long service life, corrosion resistance and extremely high material purity are called for. To meet these require-ments, the high-temperature zone (“hot zone”) in CZ units consists almost entirely of graphite components.

SGL Group produces all the graphite components for CZ units – also as a set.

Specialty graphites for silicon crystal pulling

Application-specific specialty graphites for CZ units

Applications ProductsGraphite

Soft felt Rigid felt C/C SiC coatedisostatic extruded vibration-

molded

Monocrystal pulling

Crucibles ○ ○Heaters ○

Heat shields ○ ○Reflectors ○ ○ ○Insulation ○ ○

These include heaters, crucibles, reflectors, and heat shields made from fine-grain graphite or carbon fiber-reinforced carbon, as well as insulating components produced from graphite felts. From our broad carbon and graphite range, we select the best materials to suit the particular operating conditions. For components destined for silicon/silicon oxide atmospheres, our long-life isostatic graphite R6510 is first choice. Irrespective of this, the service life of highly stressed components can be increased with our SiC coatings.

c Support crucible made from C/C c Rigid felt cylinder for insulation

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The block casting process, also known as the DSS (directional solidification system) or VGF (vertical gradient freeze) process, now produces most of the wafers processed in the PV indus-try. For efficient manufacture of ever larger silicon blocks, the demands on graphite components in the “hot zone” are con-tinually increasing. The important factors are the available dimensions, high strength and corrosion resistance, optimum thermal conductivity, and high material purity. Our products meet all these requirements.

For DSS furnaces, we supply a complete range of graphite components, either individually or as a set. The heater, bottom and side plates are produced from fine-grain graphite, thermal insulating plates from graphite rigid felts, and crucible cover plates and fastening elements from carbon fiber-reinforced carbon. Our customers benefit from high material quality, our wide portfolio based on our own semi-finished product manufacture, and the large range of sizes available. For example, our large rigid felt insulating plates (1524 x 1219 mm/60" x 48") make it possible to achieve much better utilization of the plates.

c SIGRATHERM MFA graphite rigid felt board c SIGRABOND Performance

Specialty graphites for the production of multi-crystalline silicon blocks

Application-specific specialty graphites for DSS/VGF units

Applications ProductsGraphite

Soft felt Rigid felt C/C SiC coatedisostatic extruded vibration-

molded

Multi-crystalline casting

Heaters ○ ○ ○Base plates ○ ○

Side/bottom plates ○Cover plates ○

Insulation ○Fastening elements ○

SPECIALTy GRAPhITES FOR ThE PhOTOVOLTAIC InDUSTRy

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In PECVD (plasma-enhanced chemical vapor deposition) units, the exact positioning of the solar wafers is crucial. Only in this way optimum coating results can be achieved – to produce solar cells with the highest possible yield. We support our customers in this market with precision-made carrier systems made from dimensionally stable specialty graphites.

SGL Group supplies both solid graphite boats made from high-purity isostatic graphite and wafer carriers made from carbon fiber-reinforced carbon (C/C) in all current sizes. Our specially developed material SIGRABOND Performance offers particular advantages here. Due to its extreme high rigidity and light weight, it allows very slender and efficient wafer carriers to be produced.

c Graphite carrier boats for solar wafers

c C/C carrier frame for solar wafers

a Trial assembly of a converter at SGL Group

Specialty graphites for antireflective coating in PECVD units

Application-specific specialty graphites for PECVD units

Applications ProductsGraphite

Soft felt Rigid felt C/C SiC coatedisostatic extruded vibration-

molded

PECVD coating(antireflexion)

Graphite boats ○ ○Wafer carriers ○ ○

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Partners for the optimization of converter units A major manufacturer of polysilicon complained about unsatisfactory output from his converters.

Together, we redesigned heaters and graphite installations and selected optimum components. Using near-net- shape technology, we also developed new insulating cylinders made from graphite rigid felt.

The result: around a 20 % higher STC-TCS conversion rate and reduced energy and overall plant costs.

This is just one example of an application- specific optimized solution from the SGL Group.

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Fine-grain graphites for the photovoltaic industryMany applications in the photovoltaic industry benefit from our wide range of isostatic, extruded, and vibration-molded fine-grain graphites and their outstanding properties:

High mechanical strength

Consistently high quality

High purity

Large range of dimensions

High corrosion resistance

Excellent heat resistance

13FInE-GRAIn GRAPhITES

Our SIGRAFINE materials span the complete range of fine-grain graphites from isostatic and extruded to vibration-molded graphites.For the many different applications in the photovoltaic industry, we supply the optimum material in the usual market sizes.For heater systems, certain of our isostatic and extruded graphite grades are suitable. Very long tubes can be produced in one piece with excellent results from extruded graphite. For extra-large components, we stock special vibration-molded and isostatic graphite grades.

All components produced from the above-mentioned materials can be supplied, if necessary, in extremely high purity and generally also with a SiC coating. We generally use isostatic graphites with a suitable thermal expansion coefficient as a substrate for SiC coating, but can use other graphites or carbon/carbon materials as well to satisfy specific customer requirements.

SIGRAFINE® fine-grain graphites Isostatic, extruded, vibration-molded.

�+�More information under: www.sglgoup.com/ProductionprocessFine-graingraphites

3) Ø 400 ... 780 mm (Ø 16 ... 31 in); ¨ 500 x 500, ... 610 x 760 mm (¨ 20 x 20, ... 24 x 30 in) 4) Ø 760 ... 1360 mm (Ø 30 ... 54 in); ¨ 630 x 1300 x 1420 mm (¨ 25 x 51 x 56 in)

1) Specifiction limit for ash values: < 30 ppm 2) Specifiction limit for ash values: < 5 ppm

Material data of our isostatic SIGRAFINE® fine-grain graphite

Typical properties UnitsIsostatic graphite

R6300 R6340 R6500 R6510 R6650Average grain size µm (µin) 20 (800) 15 (600) 10 (400) 10 (400) 7 (300)Bulk density g/cm3 1.73 1.72 1.77 1.83 1.84Resistivity µΩm 16 12 14 13 14Flexural strength MPa 40 45 50 60 65Compressive strength MPa 85 90 110 130 150Thermal expansion 20 – 200 °C (68 – 392 °F) 10-6 K-1 2.7 3.2 4.2 4.2 4.1Ash content ppm ≤ 200 ≤ 200 ≤ 200 ≤ 200 ≤ 200Ash content (purified, P30) 1) ppm ≤ 10 ≤ 10 ≤ 10 ≤ 10 ≤ 10Ash content (high-purity, P5) 2) ppm ≤ 2 ≤ 2 ≤ 2 ≤ 2 ≤ 2

Material data of our extruded and vibration-molded SIGRAFINE® fine-grain graphite

Typical properties UnitsExtruded graphite Vibration-molded graphite

HLM3) SDR MKUN MKUS4)Average grain size mm (in) 0.8 (0.03) 0.2 (0.008) 0.8 (0.03) 0.8 (0.03)Bulk density g/cm3 1.72 1.75 1.67 1.79Resistivity µΩm 7.8/9.5 9.0 10/12 8/9Flexural strength MPa 19/19 33 10/10 18/17Compressive strength MPa 40/39 – 25/25 41/39Thermal expansion 20 – 200 °C (68 – 392 °F) 10-6 K-1 3.0/3.5 2.2 2.3/3.2 2.7/3.3Ash content ppm ≤ 800 ≤ 500 ≤ 700 ≤ 700Ash content (purified, P30) 1) ppm ≤ 10 ≤ 10 ≤ 10 ≤ 10Ash content (high-purity, P5) 2) ppm ≤ 2 ≤ 2 ≤ 2 ≤ 2

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Our soft felts offer a unique combination of thermal, chemical and textile properties. This makes them highly suitable for insulation of Czochralski crystal growing units.

Thanks to their special manufacturing process, our SIGRATHERM graphite soft felts have very low thermal conductivity.They also have the unique advantage of an extremely homo-geneous thickness and density distribution throughout the roll length. As a result, our soft felts guarantee a uniform and consistently high insulating effect. Our SIGRATHERM graphite soft felts are also supplied in ultra-high purity and special customer-tailored dimensions.

SIGRATHERM® graphite soft felts For optimum thermal insulation.

Material data of our SIGRATHERM® graphite soft felt

Typical properties Units GFA5 GFA10Thickness mm (in) 6 (1/4) 11.5 (1/2)Area weight g /m2 500 1000Width mm (in) 1220 (48) 1270 (50)Length m (ft) 25 – 30 (82 – 98) 25 – 30 (82 – 98)Ash content ppm ≤ 400 ≤ 400Ash content (purified) ppm ≤ 20 ≤ 20Maximum application temperature °C (°F) 2000 (3600) in vacuum or inert gas

c SIGRATHERM soft felt

Ther

mal

con

duct

ivity

[Wm

-1K-1]

Temperature [°C/°F]

0.1

0.2

0.3

0.4

0.5

0.6

0

Thermal conductivity of SIGRATHERM GFA as a function oftemperature (vacuum/inert gas atmosphere)

Inert gas

Vakuum

200/390 2000/36001000/1800

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SIGRATHERM® graphite rigid felts For mechanically stable thermal insulation.

Sheets and cylinders produced from SIGRATHERM graphite rigid felts are particularly valued for their consistently good thermal insulating properties. In addition, they are corrosion- resistant, easy to process, and allow self-supporting structures for insulating even relatively large components.

Besides SIGRATHERM insulating sheets as semi-finished products, we also supply ready-to-use components to customer-specific requirements.

Thermal conductivity of SIGRATHERM MFA as a function oftemperature (inert gas atmosphere)

Temperature [°C/°F]

00

0.2

0.4

0.6

0.8

1.0

1000/1830 2000/3600

Ther

mal

con

duct

ivity

[Wm

-1K-1]

With our innovative connection solutions, we can, for example, supply tailor-made cylinders in virtually any size, which is particularly beneficial to polysilicon manufacturers. We also supply rigid felts in ultrapure quality for semiconductor applications.

One or more layers of graphite foil inseparably attached to the insulating felt can be applied as a convection barrier and re-flective coating. For mechanical surface protection, we supply an insulating composite comprising felt covered on both sides with C/C fabric.

c SIGRATHERM rigid felt with different surface layers

CARBOn AnD GRAPhITE FELTS

Material data of our SIGRATHERM® graphite rigid felt

Typical properties UnitsBoards Cylinder

MFA RFA MFA RFABulk density g/cm3 0.2 0.2 0.2 0.2Compressive strength MPa 1 1 1 1Flexural strength MPa 1 1 1 1Moisture absorption % < 1.0 < 1.0 < 1.0 < 1.0Ash content ppm ≤ 1000 ≤ 1000 ≤ 1000 ≤ 1000Ash content (purified) ppm < 20 < 20 < 20 < 20

Length/Width Diameter max /Length max mm (in) 1524/1219 (60/48) 1524/1219 (60/48)

unlimited

2000/2500 (79/98)

Thickness Wall thickness max mm (in) 20 – 400 (3/4 – 16) 20 – 400 (3/4 – 16)

150 (6)

300 (12)

Maximum application temperature °C (°F) 2000 (3600) in an inert gas atmosphere or vacuum

16 CARBOn FIBER-REInFORCED CARBOn

SIGRABOND® carbon fiber-reinforced carbon (C/C) For lightweight, rigid, durable carrier structures.

c SIGRABOND Performance and SIGRABOND Standard

Material data of our SIGRABOND® carbon-fiber reinforced carbon

Typical properties UnitsPlates Rotationally symmetric parts

Performance Standard FilWoundBulk density g/ cm3 1.5 1.5 1.4Flexural strength MPa 200 150

depending on the structure of the lay-upElastic modulus GPa 70 60

Interlaminar shear strength MPa 8 8Ash content ppm ≤ 1000 ≤ 1000 ≤ 1000Ash content (purified) ppm ≤ 10 ≤ 10 ≤ 10

Length/Width 1)

Diameter max /Length maxmm (in)

1220 x 1220/2450 x 1220 (48 x 48/96 x 48)

special dimensions on request

1220 x 1220/2450 x 1220 (48 x 48/96 x 48)

special dimensions on request

2000/2500 (79/98)

Thickness Wall thickness max mm (in)

1.8 – 15 (0.07 – 0.6) 0.7 – 30 (0.03 – 1.2) 100 (4)

Maximum application temperature °C (°F) 2000 (3600) in vacuum or inert gas

High mechanical loadbearing capacity, light weight, low thermal expansion, extremely good corrosion resistance and thermal stability, high purity: these are the properties of our SIGRABOND composites.

Besides plates and profiles, we also produce rotationally symmetrical components such as crucibles and cylinders from SIGRABOND.Our SIGRABOND Performance is a newly developed C/C plate with improved rigidity for even lighter-weight compo-nents such as wafer carrier systems for PEVCD units or cover plates for DSS units. SIGRABOND FilWound products are used mainly as C/C support crucibles in CZ units. Our C/C semi-finished products can be machined or finished with an SiC coating according to customer requirements.

1) Standard dimensions

α =

x × 10

-6/K

Temperature [°C/°F]

Coefficient of thermal expansion

-2

0

0

2

4

6

8

10

12

400/750 1200/2200 2000/3600

parallel to direction of fiber alignment

vertical to direction of fiber alignment

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SIGRAFINE® SiC CoatingTo extend the service life of graphite components.

Material data of SIGRAFINE® SiC Coating

Typical properties Units Values Analysis techniqueStructure beta (cubic) 3C polytype XRDOrientation Fraction [%] 111 preferred XRDBulk density g/cm3 3.2 XRDStoichiometry 1:1 Si/C XPSHardness GPa 40 NanoindentationFracture toughness MPa m1/2 3.0 Vickers identerThermal expansion 100 – 600 °C (212 – 1112 °F) 10-6 K-1 4.3 DilatometerE-modulus GPa 435 NanoindentationTypical film thickness µm 100 Beta backscatterSurface roughness µm 2.5 Profilometer

Purity data of SIGRAFINE® SiC Coating (glow discharge mass spectroscopy)

Element ppm Element ppmSodium < 0.05 Copper < 0.01Magnesium < 0.01 Zinc < 0.05Aluminum < 0.04 Gallium < 0.05Phosphorus < 0.01 Germanium < 0.05Sulfur < 0.04 Arsenic < 0.005Potassium < 0.05 Indium < 0.01Calcium < 0.05 Tin < 0.01Titanium < 0.005 Antimony < 0.01Vanadium < 0.001 Tungsten < 0.01Chromium < 0.05 Tellurium < 0.01Manganese < 0.005 Lead < 0.01Iron < 0.01 Bismuth < 0.01Nickel < 0.005 c Micrograph of SiC surface

SIGRAFINE SiC Coating is a dense, wear-resistant silicon carbide coating with high corrosion and heat resistance and an excellent thermal conductivity. We apply SiC in thin layers onto the graphite using the chemical vapor deposition (CVD) process.The coating improves product quality, increases process efficiency, and so reduces the overall operating costs of our customers.

With this coating, we extend the service life of graphite components and achieve the high-purity surface structures required in processing semiconductor materials. SGL Group supplies SiC-coated products made from high-strength isostatic graphite and carbon fiber-reinforced carbon. These include components for fluidized-bed reactors and STC-TCS converters as well as reflectors for CZ units and wafer carriers for PECVD, Si epitaxy, and MOCVD units.

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We will find the best solution – in partnership with you.The fascinating potential of carbon as a material excites us and inspires us to develop optimum solutions in partnership with our customers.

With our comprehensive material portfolio and valuable specialist know-how, we can manufacture tailored products – even for the most challenging applications.

Consistently high quality, a global presence, innovative strength, and the extensive experience of our employees make us a reliable partner to our customers.

Whatever challenges you face, together we will find the best solution.

19SGL GROUP – ThE CARBOn COMPAny

b 3D winding of a SIGRABOND FilWound crucible at SGL Group

SGL Group – The Carbon Company. A leading global manufacturer of carbon-based products.

Unique product portfolio Innovative technologies and solutions Production sites close to sales markets Technology & Innovation Center in Germany with international networks

We have wide-ranging expertise in raw materials, advanced manufacturing processes, and long-standing application and engineering know-how. We have a comprehensive portfolio of carbon, graphite, and carbon fiber products and our integrated value chain covers everything from carbon fibers to composites. With a global sales and distribution network and modern production sites in Europe, North America, and Asia, we are close to our customers throughout the world.

We use this broad base to offer our customers the best solutions possible. That’s how we live up our claim: Broad Base. Best Solutions. This claim is also upheld by our corporate SGL Excellence philosophy of continuous improvement.

�+�More information can be found by visiting: www.sglgroup.com

sglgroup sglgroup

® registered trademark of SGL CARBON SE 07 2015/0 2NÄ Printed in GermanyThis information is based on our present state of knowledge and is intended to provide general notes on our products and their uses. It should therefore not be construed as guaranteeing specific properties of the prod-ucts described or their suitability for a particular application. Any existing industrial property rights must be observed. The quality of our products is guaranteed under our “General Conditions of Sale”.

Graphite Materials & SystemsSGL CARBON GmbH Soehnleinstrasse 8 | 65201 Wiesbaden/Germanywww.sglgroup.com/gms

Contact

EUROPE/MIDDLE EAST/AFRICASGL CARBON GmbHDrachenburgstrasse 153170 Bonn/Germanygms-europe@sglgroup.com

ASIA/PACIFICSGL CARBON Far East Ltd.12 Fl, Shanghai Oriental Plaza,31 Wujiang Road Shanghai 200041/PR Chinagms-asia@sglgroup.com

AMERICASSGL CARBON LLC900 Theresia StreetPA 15857 St. Marys/USAgms-americas@sglgroup.com