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SiC Seed Crystal Diameter 153mm 155mm 203mm 205mm 208mm PVT
Product Details:
| Place of Origin: | China |
| Brand Name: | ZMSH |
Payment & Shipping Terms:
| Minimum Order Quantity: | 1-3 |
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Detail Information |
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| Crystal Structure: | 4H, 6H, 3C (most Common: 4H For Power Devices) | Band Gap: | 3.26 (4H), 3.02 (6H), 2.36 (3C) EV /300K |
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| Hardness (Mohs): | 9.2-9.6 | Off-cut Angle: | Typically 4° Or 8° Toward <11-20> |
| Highlight: | 203mm SiC Seed Crystal,153mm SiC Seed Crystal,208mm SiC Seed Crystal |
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Product Description
SiC seed crystals diameters of 153, 155, 205, 203, and 208 mm PVT
Abstract of the SiC Seed Crystals
Silicon carbide (SiC) has emerged as a vital material in the semiconductor industry due to its unique properties, such as a wide bandgap, high thermal conductivity, and exceptional mechanical strength. SiC seed crystals play a crucial role in the growth of high-quality SiC single crystals, which are essential for various applications, including high-power and high-frequency devices.
SiC seed crystals are small crystalline structures that serve as the starting point for the growth of larger SiC single crystals. They possess the same crystal orientation as the desired final product, allowing for the continuation of the crystal lattice structure during growth. The seed crystal acts as a template, guiding the arrangement of atoms in the growing crystal.
The Attribute Table of the SiC Seed Crystal
| Property | Value / Description | Unit / Notes |
| Crystal Structure | 4H, 6H, 3C (most common: 4H for power devices) | Polytypes vary in stacking sequence |
| Lattice Parameters | a=3.073Å, c=10.053Å (4H-SiC) | Hexagonal system |
| Density | 3.21 | g/cm³ |
| Melting Point | 3100 (sublimes) | °C |
| Thermal Conductivity | 490 (∥c), 390 (⊥c) (4H-SiC) | W/(m·K) |
| Thermal Expansion | 4.2×10⁻⁶ (∥c), 4.68×10⁻⁶ (⊥c) | K⁻¹ |
| Band Gap | 3.26 (4H), 3.02 (6H), 2.36 (3C) | eV /300K |
| Hardness (Mohs) | 9.2-9.6 | Second only to diamond |
| Refractive Index | 2.65 @ 633nm (4H-SiC) | |
| Dielectric Constant | 9.66 (∥c), 10.03 (⊥c) (4H-SiC) | 1MHz |
| Breakdown Field | ~3×10⁶ | V/cm |
| Electron Mobility | 900-1000 (4H) | cm²/(V·s) |
| Hole Mobility | 100-120 (4H) | cm²/(V·s) |
| Dislocation Density | <10³ (best commercial seeds) | cm⁻² |
| Micropipe Density | <0.1 (state-of-the-art) | cm⁻² |
| Off-cut Angle | Typically 4° or 8° toward <11-20> | For step-controlled epitaxy |
| Diameter | 100mm (4"), 150mm (6"), 200mm (8") | Commercial availability |
| Surface Roughness | <0.2nm (epi-ready) | Ra (atomic level polishing) |
| Orientation | (0001) Si-face or C-face | Affects epitaxial growth |
| Resistivity | 10²-10⁵ (semi-insulating) | Ω·cm |
Diameters of SiC Seed Crystals
The typical diameters for SiC seed crystals range from 153 mm to 208 mm, including specific sizes such as 153 mm, 155 mm, 203 mm, 205 mm, and 208 mm. These dimensions are selected based on the intended application and the desired size of the resulting single crystal.
1. 153 mm and 155 mm Seed Crystals
These smaller diameters are often used for initial experimental setups or for applications that require smaller wafers. They allow researchers to explore various growth conditions and parameters without the need for larger, more costly equipment.
2. 203 mm and 205 mm Seed Crystals
Mid-range diameters like these are commonly used for industrial applications. They provide a balance between material usage and the size of the final single crystals. These sizes are often employed in the production of power electronics and high-frequency devices.
3. 208 mm Seed Crystals
The largest seed crystals available, such as those with a diameter of 208 mm, are typically utilized for high-volume production. They enable the growth of larger single crystals, which can be sliced into multiple wafers for manufacturing. This size is particularly advantageous in the automotive and aerospace industries, where high-performance components are essential.
Growth Methods for SiC Seed Crystals
The growth of SiC single crystals usually involves several methods, with the physical vapor transport (PVT) method being the most prevalent. This process is characterized by the following steps:
Preparation of the Graphite Crucible: SiC powder is placed at the bottom of a graphite crucible. The crucible is then heated to the sublimation temperature of SiC.
Placement of the Seed Crystal: The SiC seed crystal is positioned at the top of the crucible. As the temperature gradients are established, the SiC powder sublimates into a vapor.
Condensation: The vapor rises to the top of the crucible, where it condenses on the surface of the SiC seed crystal, facilitating the growth of the single crystal.
Thermodynamic Properties
The thermodynamic behaviors of SiC during the growth process are critical. The temperature gradient and pressure conditions must be carefully controlled to ensure optimal growth rates and crystal quality. Understanding these properties aids in refining growth techniques and improving yield.
Challenges in SiC Seed Crystal Production
While the growth of SiC seed crystals is well-established, several challenges persist:
1. Adhesive Layer Density
When attaching seed crystals to the growth holders, issues such as the uniformity of the adhesive layer can lead to defects. Poor adhesion can result in voids or detachment during the growth process.
2. Surface Quality
The surface quality of the seed crystal is crucial for successful growth. Any imperfections can propagate through the crystal lattice, leading to defects in the final product.
3. Cost and Scalability
Producing larger SiC seed crystals is often more expensive and requires advanced manufacturing techniques. Balancing cost with quality and scalability remains a challenge for the industry.
Q&A
Q:What's the most common orientations used in SiC growth?
A: Different orientations of SiC seed crystals yield single crystals with varying characteristics. The most common orientations used in SiC growth are 4H-SiC and 6H-SiC, each with distinct electrical and thermal properties. The choice of orientation affects the performance of the final device, making the selection of the appropriate seed crystal crucial.