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SiC Seed Crystals Specifically Those With Diameters Of 153, 155, 205, 203 And 208 Mm
Product Details:
| Place of Origin: | CHINA |
| Brand Name: | ZMSH |
Payment & Shipping Terms:
| Minimum Order Quantity: | 5 |
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| Price: | undetermined |
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Detail Information |
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| Crystal Structure: | 4H, 6H, 3C (most Common: 4H For Power Devices) | Hardness (Mohs): | 9.2-9.6 |
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| Orientation: | (0001) Si-face Or C-face | Resistivity: | 10²-10⁵ (semi-insulating) Ω·cm |
| Highlight: | SiC Seed Crystals,208Mm Diameter SiC Seed Crystals,Hardness Mohs 9.2 SiC Seed Crystals |
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Product Description
SiC seed crystals, specifically those with diameters of 153, 155, 205, 203, and 208 mm
Abstract of the SiC seed crystals
SiC seed crystals are small crystals with the same crystal orientation as the desired crystal, serving as seeds for single crystal growth. Different orientations of seed crystals yield single crystals with varying orientations. Based on their applications, seed crystals can be categorized into CZ (Czochralski) pulled single crystal seeds, zone-melted seeds, sapphire seeds, and SiC seeds.
SiC materials possess advantages such as a wide bandgap, high thermal conductivity, high critical breakdown field strength, and high saturated electron drift velocity, making them highly promising in semiconductor manufacturing.
SiC seed crystals play a crucial role in the semiconductor industry, and their preparation processes are vital for crystal quality and growth efficiency. Choosing and preparing suitable SiC seed crystals is foundational for SiC crystal growth. Different growth methods and control strategies directly impact the quality and performance of the crystals. Researching the thermodynamic properties and growth mechanisms of SiC seed crystals helps optimize production processes, enhancing both crystal quality and yield.
The Attribute Table of the SiC seed crystals
| 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 | 153mm , 155mm , 203mm | 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 |
Physical vapor transport (PVT) methods
Typically, SiC single crystals are generated using physical vapor transport (PVT) methods. The process involves placing SiC powder at the bottom of a graphite crucible, with the SiC seed crystal positioned at the top. The graphite crucible is heated to the sublimation temperature of SiC, causing the SiC powder to decompose into vapor species such as Si vapor, Si2C, and SiC2. Under the influence of an axial temperature gradient, these gases rise to the top of the crucible, where they condense on the surface of the SiC seed crystal, forming SiC single crystals.
Currently, the diameter of the seed crystal used for SiC single crystal growth must match that of the target crystal. During growth, the seed crystal is fixed to a seed holder at the top of the crucible using adhesive. However, issues such as surface processing accuracy of the seed holder and uniformity of the adhesive application can lead to pore formation at the adhesive interface, resulting in hexagonal void defects.
To address the issue of adhesive layer density, various solutions have been proposed by companies and research institutions, including improving the flatness of graphite plates, increasing the uniformity of adhesive film thickness, and incorporating flexible buffer layers. Despite these efforts, problems with adhesive layer density persist, and there is a risk of seed crystal detachment. A solution involving bonding the wafer to graphite paper that overlaps the top of the crucible has been implemented, effectively resolving the adhesive layer density issue and preventing seed crystal detachment.
Q&A
Q:What factors affect the quality of SiC seed crystals?
A:1. Crystalline Perfection
2. Polytype Control
3. Surface Quality
4. Thermal/Mechanical Properties
5. Chemical Composition
6. Geometric Parameters
7. Process-Induced Factors
8. Metrology Limitations
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