Langasite Wafers and Boules (La3Ga5SiO14)
- Attractive piezo-electric coupling
- Excellent temperature stability
- Prototype material available
Langasite wafers are substrates fabricated from single crystal langasite suitable for use in surface acoustic wave applications. Such wafers are most commonly specified as 3" diameter with a reference flat. Wafer orientation is customer specified based on desired component performance characteristics. A high quality, low damage surface is prepared on one major (propagating) surface by polishing. The back side is usually lapped to a rougher finish to attenuate unwanted vibration modes.
Langasite Wafer Specifications
LGS 140-25-100/500
| Langasite Wafer, YXIs /0/140/25 | Tolerance |  |
|
| Cut, A1 | 138.5° | ± 0.1° | |
| Cut, A2 | 26.7° | ± 0.1° | |
| Diameter D mm | 100mm | ±0.25mm | |
| Thickness T.mm | 0.50mm | ±0.03mm | |
| Reference Flat F1,mm | 32.0mm | ±2.50mm | |
| Secondary Flat F2, mm | 11.0mm | ±2.00mm | |
| Surface | |||
| Front Surface Finish | Polished Ra < 0.7 nm | ||
| Back Surface Finish | Lapped, 0.4 pm < Ra < 0.6μm | ||
| Flatness | < 10μm | ||
| Front Surface Defects | |||
| Scratches, cracks, contamination, others (dimples, pits. orange peel) | No such defects by visual inspection | ||
| Chips | |||
| Edge chips Surface | Radial depth < 0.5mm: Peripheral chord length < 1.0mm No chips by visual inspection |
||
| Bevel | Rounded Edge | ||
| Langasite Wafer, YXIs /0/140/25 | Tolerance | |
|
| Cut, A1 | 140° | ± 0.1° | |
| Cut, A2 | 25° | ± 0.1° | |
| Diameter D mm | 76mm | ±0.25mm | |
| Thickness T.mm | 0.50mm | ±0.03mm | |
| Reference Flat F1,mm | 22.0mm | ±2.50mm | |
| Secondary Flat F2, mm | 11.0mm | ±2.00mm | |
| Surface | |||
| Front Surface Finish | Polished Ra < 0.7 nm | ||
| Back Surface Finish | Lapped, 0.4 pm < Ra < 0.6μm | ||
| Flatness | < 10μm | ||
| Front Surface Defects | |||
| Scratches, cracks, contamination, others (dimples, pits. orange peel) | No such defects by visual inspection | ||
| Chips | |||
| Edge chips Surface | Radial depth < 0.5mm: Peripheral chord length < 1.0mm No chips by visual inspection |
||
| Bevel | Rounded Edge | ||
LGS 138.5-26.7-76/500
| Langasite Wafer, YXIs /0/138.5/26.7 | Tolerance | |
|
| Cut, A1 | 138.5° | ± 0.1° | |
| Cut, A2 | 26.7° | ± 0.1° | |
| Diameter D mm | 100mm | ±0.25mm | |
| Thickness T.mm | 0.50mm | ±0.03mm | |
| Reference Flat F1,mm | 22.0mm | ±2.50mm | |
| Secondary Flat F2, mm | 11.0mm | ±2.00mm | |
| Surface | |||
| Front Surface Finish | Polished Ra < 0.7 nm | ||
| Back Surface Finish | Lapped, 0.4 pm < Ra < 0.6μm | ||
| Flatness | < 10μm | ||
| Front Surface Defects | |||
| Scratches, cracks, contamination, others (dimples, pits. orange peel) | No such defects by visual inspection | ||
| Chips | |||
| Edge chips Surface | Radial depth < 0.5mm: Peripheral chord length < 1.0mm No chips by visual inspection |
||
| Bevel | Rounded Edge | ||
| Langasite Wafer, YXIs /0/138.5/26.7 | Tolerance | |
|
| Cut, A1 | 138.5° | ± 0.1° | |
| Cut, A2 | 26.7° | ± 0.1° | |
| Diameter D mm | 76mm | ±0.25mm | |
| Thickness T.mm | 0.50mm | ±0.03mm | |
| Reference Flat F1,mm | 32.0mm | ±2.50mm | |
| Secondary Flat F2, mm | 11.0mm | ±2.00mm | |
| Surface | |||
| Front Surface Finish | Polished Ra < 0.7 nm | ||
| Back Surface Finish | Lapped, 0.4 pm < Ra < 0.6μm | ||
| Flatness | < 10μm | ||
| Front Surface Defects | |||
| Scratches, cracks, contamination, others (dimples, pits. orange peel) | No such defects by visual inspection | ||
| Chips | |||
| Edge chips Surface | Radial depth < 0.5mm: Peripheral chord length < 1.0mm No chips by visual inspection |
||
| Bevel | Rounded Edge | ||