Thin-Film Lithium Niobate on Insulator (LNOI) wafers are advanced photonic substrates used for integrated optical, microwave photonic, and quantum systems.
The structure consists of a single-crystal lithium niobate thin film bonded onto a SiO₂ insulating layer and supported by a silicon substrate.
This configuration provides strong optical confinement, ultra-low propagation loss, and high electro-optic efficiency, making it a key platform for integrated photonics.
What is Thin-Film Lithium Niobate (TFLN)
Thin-Film Lithium Niobate (TFLN) refers to a sub-micron crystalline LiNbO₃ layer engineered for optical waveguide and electro-optic applications.
Compared with bulk lithium niobate, TFLN enables tighter optical confinement, smaller device footprint, and higher integration density.
TFLN is typically implemented on LNOI wafers to form a complete integrated photonic platform.
Основные характеристики
- Ultra-low optical loss < 0.05 dB/cm @ 1550 nm
- High electro-optic coefficient (r₃₃ up to 90 pm/V)
- Sub-micron waveguide compatibility (<1 μm)
- CMOS-compatible integration with Si / SiN platforms
- High thermal stability (~1140°C Curie temperature)
- Multiple crystal cuts: X-cut / Y-cut / Z-cut
- Wafer sizes: 3 inch / 4 inch / 6 inch / 8 inch
Wafer Structure
| Layer | Материал | Function |
|---|---|---|
| Top Layer | LiNbO₃ Thin Film (TFLN) | Electro-optic & nonlinear optical functionality |
| Middle Layer | SiO₂ (Buried Oxide) | Optical isolation & confinement |
| Bottom Layer | Si / Quartz / Sapphire | Mechanical support & CMOS compatibility |
Технические характеристики
Wafer Specifications
| Параметр | Значение |
|---|---|
| Wafer Diameter | 3″, 4″, 6″, 8″ |
| Total Thickness | 525 ± 25 μm |
| Лук | ±50 μm |
| Warp | <50 μm |
| LTV | <1.5 μm (5×5 mm², 95%) |
Thin-Film Lithium Niobate Layer
| Параметр | Значение |
|---|---|
| Материал | Single-crystal LiNbO₃ |
| Толщина | 300 nm – 1000 nm |
| Orientation Accuracy | ±0.5° |
| Шероховатость поверхности | Ra < 1 nm |
| Bonding Defects | No defects >1 mm |
Buried Oxide Layer (SiO₂)
| Параметр | Значение |
|---|---|
| Материал | SiO₂ |
| Толщина | 100 nm – 2 μm (customizable) |
| Равномерность | ±5% |
Fabrication Process
LNOI wafers are manufactured using semiconductor-grade processes:
- Ion implantation for controlled layer separation
- Wafer bonding onto insulating substrates
- High-temperature annealing for crystal stabilization
- Chemical Mechanical Polishing (CMP) for surface planarization
- Final optical and structural quality inspection
Key Applications
- High-speed optical communication (100G–800G modulators)
- Quantum photonics (entangled photon generation, QKD systems)
- Microwave photonics (RF signal processing, mmWave systems)
- Nonlinear optics (frequency conversion, optical combs)
- Integrated sensing systems (biochemical and optical resonators)
Performance Advantage vs Bulk LiNbO₃
| Недвижимость | Bulk LiNbO₃ | LNOI Thin Film |
|---|---|---|
| Optical Loss | Higher | <0.05 dB/cm |
| Integration | Низкий | High-density photonics |
| Device Size | Large | Sub-micron scale |
| CMOS Compatibility | No | Yes |
| Modulation Efficiency | Умеренный | High (Vπ ~1V achievable) |
Параметры настройки
| Option | Описание |
|---|---|
| Crystal Cut | X-cut / Y-cut / Z-cut |
| Толщина пленки | 300 nm – 1000 nm |
| Substrate | Si / Quartz / Sapphire |
| Oxide Layer | 100 nm – 2 μm (custom) |
| Doping | MgO-doped LiNbO₃ available |
Контроль качества
| Test Item | Метод |
|---|---|
| Optical Loss | Waveguide propagation test |
| Шероховатость поверхности | AFM measurement |
| Равномерность толщины | Mapping system |
| Bonding Quality | IR inspection |
| Плоскость | Wafer metrology |
Engineering Capability
ZMSH provides full-process support for LNOI wafer development:
- Thin-film design optimization
- Wafer bonding process engineering
- Photonic device fabrication support
- Nanofabrication (EBL / IBE)
- Optical performance testing and validation
Supports both R&D prototyping and scalable small-batch production up to 8-inch wafers.
ЧАСТО ЗАДАВАЕМЫЕ ВОПРОСЫ
What is LNOI used for
LNOI wafers are widely used in optical communication, quantum photonics, nonlinear optics, and integrated photonic circuits.
What is the typical thin-film thickness
Typical lithium niobate thin-film thickness ranges from 300 nm to 1000 nm.
Why use LNOI instead of bulk lithium niobate
LNOI offers lower optical loss, higher integration density, and CMOS-compatible photonic integration.
Can LNOI integrate with silicon photonics
Yes, LNOI is fully compatible with silicon and silicon nitride photonic platforms.
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