Due to its superior mechanical properties, chemical stability, and light transmission, single- crystal sapphire is becoming an increasingly significant material for high-reliability electronics.
Features of Single Crystal Sapphire
- High strength, high rigidity, high anti-abrasion, high anti-heat, high anti-corrosion characteristics, and high anti-plasma characteristics: Single crystal sapphire is frequently utilized for precision mechanical parts because of these qualities.
- Stable dielectric constant, very low dielectric loss, good electric insulation: Single-crystal sapphire is employed as a super-high frequency substratum material. It is also utilized as a microwave window and insulating material. The electronics industry now relies heavily on single-crystal sapphires.
- Excellent light transmission: As single crystal sapphire has exceptional mechanical and heat-resistant properties, it is employed in many vacuum equipment applications, reaction furnace windows, scanner windows, and optical communication caps.
- Both high heat resistance and good thermal conductivity: Single crystal sapphire is a transparent material with excellent low-temperature thermal conductivity that can be employed in a wide range of applications that need thermal conduction and heat radiation.
Unit Cell of Sapphire. Image Credit: Kyocera International, Inc.
Sapphire Single-Crystal Growth Methods
Kyocera has multiple sapphire crystal growth technologies, such as Edge-Defined Film-Fed Growth (EFG) method and Czochralski (CZ) method. We select an effective and efficient manufacturing method according to the customers’ requirements and product shapes.
EFG Method. Image Credit: Kyocera International, Inc.
Image Credit: Kyocera International, Inc.
Features of the EFG Method
- Large-size material: The sizing up of materials makes a wider variety of uses and applications possible.
- Manufacturing of a single sapphire crystal in any sectional shape requested: Cutting operations can be eliminated, resulting in a cost reduction since any desired sectional shape can be obtained in the form of ribbons, tubes, rods, and more.
- Regulation of crystal orientation: Any axis and plane can be produced by instituting proper control during crystal growth.
Features of the CZ Method
- High-Volume Production: Due to the schematics of the CZ method, this single-crystal sapphire growth method allows for for large volume production.
- A Great Option for Circular Shapes: Common products created by the Czochralski (CZ) method include sapphire wafers, substrates, and other circle-shaped or cylindric products, such as tubes.
Image Credit: Kyocera International, Inc.
Manufacturing Process for Single-Crystal Sapphire
Image Credit: Kyocera International, Inc.
Shape and Specifications
Kyocera Fine Ceramics group can produce various shapes of sapphire products, such as hollows or multi-holes. Please contact us for more details on achievable shapes and specifications.
Image Credit: Kyocera International, Inc.
As-Grown Materials
Image Credit: Kyocera Corporation
Characteristics of Single Crystal Sapphire
Source: Kyocera International, Inc.
| . |
. |
. |
Mechanical
Characteristics |
Crystallographic Structure |
Hexagonal System a＝4.763 Å and c＝13.003 Å
Rhombohedral Single crystal |
| Reference Density |
3.97×103 kg/m3 |
| Vickers Hardness |
22.5 GPa（HV(1 Load＝9.807 N)) |
| Flexural Strength |
690 MPa |
| Tensile Strength |
2250 MPa (Diameter 0.25 mm Filament 25 ℃） |
| Compressive Strength |
2,940 MPa |
| Young's Modulus |
470 GPa |
| Poisson's Ratio |
0.18～0.29 |
Thermal
Characteristics |
Melting Point |
2,053 ℃ |
Coefficient of
Linear Thermal Expansion |
40～400 ℃ C parallel to C axis 7.7×10-6/℃
40～400 ℃ C perpendicular to C axis 7.0×10-6/℃ |
| Thermal Conductivity |
20 ℃ 42 W/(m・k) |
| Specific Heat Capacity |
0.75 J/(g・K) |
| Emittance |
＜0.02 （λ＝2.6～3.7 μm 880 ℃） |
Electrical
Characteristics |
Dielectric strength |
48×106 V/m |
| Volume Resistance |
20 ℃ ＞1014 Ω・cm 500 ℃ 1011 Ω・cm |
| Dielectric Constant |
C parallel to C axis 11.5 (1 MHz）
C perpendicular to C axis 9.3（1 MHz） |
| Dielectric Loss Angle |
＜1（×10-4）（1 MHz） |
| Loss Factor |
-（×10-4） |
| Dielectric Loss Tangent |
10-4 max. |
Optical
Characteristics |
Index of Reflection |
No＝1.768
Ne＝1.760 @589 nm |
| Optical Transmission |
Refer to Fig.5 |
These figures are representative. Each Crystal Orientation has different characteristics.
Image Credit: Kyocera International, Inc.
Notes:
- The transmittance range varies depending on the thickness of the Sapphire Products
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Interfacial Reflection included
- Thickness: 1 mm
Standard Dimensional Tolerance
Source: Kyocera International, Inc.
| Nominal Dimension ：ａ |
1＞a |
1≦a≦4 |
4＜a≦25 |
25＜a≦102 |
102＜a≦190 |
190＜a |
| Tolerance （±） |
0.05 |
0.1 |
0.2 |
0.25 |
0.5 |
1 |
Machining accuracy: Tube 1.A.10.A. and standard tube thickness tolerance…±0.25. Hole diameter and standard pitch tolerance…±0.1
Sapphire Products
Substrate
Image Credit: Kyocera Corporation
Application
- High brightness LED
- Thin film substrate, piezoelectric semiconductor, superconductor, and HB-LED semiconductor
- Precision resistor, MR sensor
- Optical devices
- HIC thin film
Single-crystal sapphire is a widely used substrate material for blue, green, ultraviolet and white LEDs. This substrate possesses outstanding qualities as a base for GaN deposition, offering remarkable mass production capabilities. Furthermore, it is well- equipped to meet the demands of larger-scale requirements in the future.
Thanks to its exceptional thermal and chemical durability and lattice alignment, which match with a wide range of semiconductor materials, single-crystal sapphire can also be utilized as a base substrate in thin film deposition.
2”-8” substrate for Optical Devices. Image Credit: Kyocera International, Inc.
Standard Dimension and Tolerance. Source: Kyocera International, Inc.
| |
Size |
O.F. Length |
| 8″ |
φ200±0.25×0.725±0.05 |
55～60 |
| 6″ |
φ150±0.25×0.625±0.05 |
45～50 |
| 5″ |
φ125±0.25×0.625±0.05 |
40～45 |
| 4″ |
φ100±0.25×0.53 ±0.05 |
30～35 |
| 3″ |
φ76.2±0.25×0.43 ±0.05 |
19～25 |
| 2″ |
φ50.8±0.25×0.33 ±0.05 |
13～19 |
Specifications other than the above are available. Available sizes are dependent on a crystal orientation. Sizes and tolerances other than the above table are also available under customer requirements.
Application Examples. Image Credit: Kyocera International, Inc.
Semiconductor Process Equipment Parts
Image Credit: Kyocera International, Inc.
Application
- Handling Arm
- Microwave Entrance Tube
- Dummy Water
- Window
- Vacuum Chuck
1. Image Credit: Kyocera International, Inc.
2. Image Credit: Kyocera International, Inc.
3. Image Credit: Kyocera International, Inc.
4. Image Credit: Kyocera International, Inc.
Because of its high anti-plasma and high anti-heat qualities, it is used as a different semiconductor.
Optical Products for LCD Projectors
Applications
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Sapphire Plate
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Holder Assembled
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Polarizing Film Attached
-
Dichroic Filter
-
LCD Projector
-
Dust Control Plate
Due to its excellent thermal conductivity and optical qualities, sapphire material achieves high brightness and good picture quality for LCD projectors. Dichroic filters or other coatings are available to prevent reflections. Standard sizes are available to fit in a variety of LCD panels.
JP Patent No: 3091183, No: 3443549. US Patent No: 6577375, No: 6642989. Image Credit: Kyocera International, Inc.
Selected Transmission Layer for Wave Length Optical Transmission. Image Credit: Kyocera International, Inc.
AR Coat External Transmission. Image Credit: Kyocera International, Inc.
Optical Products
Image Credit: Kyocera International, Inc.
Application![]()
- POS Scanner Window (SOG)
- Window
- Cap for Optical Communication
- Infrared Measuring Device Window
- Coin Sensor
- Light Receiving Window Accelerating Tube
- Lamp External Tube
- High-Pressure Sodium, Xenon, and Ultra Pressure Mercury Metallic Halide
Others
Image Credit: Kyocera International, Inc.
Application
- Fiber Bar Guide
- Watch Window
- HDC Resonator Rod
- Insulating Plate and Rod
- MMR Protection Tube
- Thermocouple Protection Tube
- Single Crystal Material Sheet Holder
- Biomaterial (BIOCERAM®)