GGG (Gadolinium Gallium Garnet) / SGGG (Substituted Gadolinium Gallium Garnet)
GGG (Gadolinium Gallium Garnet) and SGGG (Substituted Gadolinium Gallium Garnet) are widely used single-crystal materials as substrates for magneto-optical epitaxial films. These substrates exhibit excellent lattice matching with magneto-optical materials such as YIG (Yttrium Iron Garnet) and BIG (Bismuth-Substituted Iron Garnet), enabling high-quality epitaxial growth. In particular, SGGG, with a larger lattice constant compared to GGG, offers superior lattice compatibility with Bi-based garnets. As a result, SGGG is extensively utilized in high-performance magneto-optical device applications.
Features
- Low dislocation density
- Excellent lattice constant uniformity
Applications
- Substrate for YIG (Yttrium Iron Garnet) epitaxial films
- Substrate for BIG (Bismuth-Substituted Iron Garnet) epitaxial films
- Optical isolators (1.3 µm / 1.5 µm bands)
- Magneto-optical devices
Material Overview
| Item | GGG | SGGG |
|---|---|---|
| Material | GGG | SGGG |
| Chemical Formula | Gd3Ga5O12 | Substituted Gd3Ga5O12 |
| Crystal Structure | Cubic System | Cubic System |
| Crystal Growth Method | CZ | CZ |
Physical Specifications
| Item | GGG | SGGG |
|---|---|---|
| Lattice Constant | 12.383 Å | 12.497 Å |
| Mohs Hardness | 8 | 7.5 |
| Density | 7.13 g/cm3 | 7.09 g/cm3 |
| Melting Point | 1725 ℃ | 1730 ℃ |
| Refractive Index (@1064 nm) | 1.954 | 1.954 |
GGG/SGGG Substrate Specifications
| Item | 3 inch | 4 inch | |
|---|---|---|---|
| Material | GGG/SGGG | ||
| Crystal Growth Method | CZ | ||
| Diameter (mm) | 76.20 ± 0.3 | 101.60 ± 0.3 | |
| Thickness (μm) | 630 ± 30 | 800 ± 30 or customizable | |
| Crystal Orientation | (111) ± 0.1° | ||
| Lattice Constant | 12.497 ± 0.003 Å | ||
| Orientation Flat | Main Flat | [-110] ± 2° | |
| Secondary Flat | [-1-12] ± 2° | ||
| Surface Quality | Flatness | In the central area of 80% effective area, Max–Min ≤ 6 µm | |
| TTV | In the central area of 80% effective area, Max–Min ≤ 6 µm | ||
| Dislocation Density | In the central area of 80% effective area, ≤ 10 cm-2 | ||
| Surface Finish | Single-side polished / Double-side polished | ||
| Surface Roughness | Ra ≤1 nm，EPI ready | ||
| Other Defects (EPI Surface) | Defect Count | In the central area of 80% effective area, ≤ 10 | |