Sapphire Windows:High-purity single-crystal alumina α-Al₂O₃ Fully customizable highly transparent

Product Overview

    Sapphire windows are high-precision optical transmission elements fabricated from high-purity single-crystal alumina (α-Al₂O₃) ingots grown by the Kyropoulos method, through multiple processes including oriented slicing, precision lapping, chemical mechanical polishing and ultra-clean cleaning. As a core material for high-end industrial viewports, it inherits all the intrinsic advantages of single-crystal sapphire, combining excellent optical homogeneity, ultra-high temperature resistance, superior mechanical hardness, strong plasma corrosion resistance and outstanding electrical insulation. It serves as a high-end upgrading alternative to traditional viewport materials such as fused silica and borosilicate glass.

    The product delivers high transmittance across a broad band from ultraviolet to mid-infrared, and supports full-dimensional customization, multiple crystal orientations and various optical coatings to meet optical, mechanical and thermal requirements under different working conditions. It is widely used in semiconductor manufacturing, high-temperature industries, laser optics, chemical research, aerospace and national defense, and can operate stably for a long time under extreme conditions such as plasma bombardment, high temperature and pressure, strong corrosion and high vacuum.

Core Technical Features

1.High-Purity Single-Crystal Material System
    Made of 4N5 grade (≥99.995%) high-purity alumina single crystal grown by the Kyropoulos method, the whole window is a complete single crystal free of grain boundaries, pores and impurity segregation. With low internal defect density and uniform stress, its optical consistency is far superior to polycrystalline ceramic and glass materials, ensuring long-term performance stability under extreme working conditions.

2.Broad-Spectrum High Transmittance Optical Performance

    It delivers excellent transmittance in a broad band from 190nm UV to 4.5μm mid-infrared. Standard C-plane double-side polished windows achieve over 85% transmittance in the visible light band. The C-plane cutting design transmits along the optical axis, effectively reducing the influence of crystal birefringence and ensuring optical imaging and detection accuracy. Functional coatings such as anti-reflection and high-reflection coatings are available upon request to further improve optical efficiency.

3.Ultra-High Temperature & Thermal Shock Resistance

    The material has a melting point of up to 2050℃ and a long-term continuous working temperature of up to 1600℃ in oxidizing atmosphere. With a thermal expansion coefficient of 5.8~7.7×10⁻⁶/℃ (varying with crystal orientation), much lower than ordinary glass, it can withstand severe thermal shock without cracking. Its dimensional deformation at high temperatures is minimal, making it suitable for extreme thermal scenarios such as tube furnaces, high-temperature reactors and plasma chambers.

4.Ultra-High Mechanical Strength & Wear Resistance
    It has a Mohs hardness of 9 (second only to diamond), a bending strength of approximately 400MPa and a compressive strength of approximately 2000MPa. The window surface is wear-resistant and scratch-resistant, and can withstand high-pressure airflow erosion, particle friction and mechanical impact. It is not easy to produce scratches and wear after long-term use, and its service life is 3-5 times that of fused silica windows, greatly reducing equipment operation and maintenance costs.

5.Strong Chemical Inertness & Plasma Resistance
    It is almost insoluble in all strong acids, alkalis and organic solvents at room temperature, and only slowly corroded by hydrofluoric acid and hot phosphoric acid. It also has excellent plasma bombardment resistance, with no particle precipitation and material aging during semiconductor etching and deposition processes, effectively ensuring chamber cleanliness and product yield.

6.Excellent Electrical Insulation & Dielectric Properties
    Intrinsic high-purity sapphire has a room-temperature resistivity higher than 10¹⁴ Ω·cm, with excellent electrical insulation, stable dielectric constant and ultra-low dielectric loss. It provides reliable electrical isolation under high-voltage and high-frequency conditions without leakage, sparking and signal interference, suitable for special scenarios such as RF plasma, high-voltage power and microwave devices.

7.Full-Parameter Customization & Precision Machining Capability
    Full-dimensional customization of shape, size, thickness, crystal orientation and surface precision is supported. Various structures such as round, square, rectangular, stepped and special shapes can be processed. Secondary processing such as precision chamfering, edge edging, drilling, slotting and metallization sealing can be completed to accurately match the installation interfaces and process requirements of various equipment.

8.Semiconductor-Grade Cleanliness Control
    Semiconductor-grade products adopt multiple ultra-clean cleaning processes, and are inspected and vacuum-packed in Class 100/Class 1000 clean rooms. Surface particles and metal ion residues are strictly controlled. They can be directly used in high-purity process scenarios such as wafer manufacturing and plasma etching, with a complete Certificate of Analysis (COA) provided.

Standard Specifications

Typical Applications

1. Semiconductor manufacturing: Chamber viewports, vacuum windows and plasma protective windows for etchers, PVD/CVD deposition equipment, resistant to plasma corrosion and ensuring process cleanliness
2. High-temperature industry: Observation windows for tube furnaces, high-temperature sintering furnaces and high-pressure reactors, withstanding 1600℃ high temperature and thermal shock for long-term operation
3. Optical laser field: High-power laser output protective windows, spectrometer detection windows, UV/IR optical instrument windows, sensor protective lenses
4. Chemical & scientific research: Light-transmitting viewports for highly corrosive reaction chambers, high-pressure fluid observation windows, laboratory high-temperature reactor windows
5. Aerospace & special fields: IR detection windows, radiation-resistant optical protective components, deep-sea detection pressure-resistant viewports

Quality Control
    A full-process quality control system covering from ingot selection to finished product delivery is established, and each window undergoes strict multi-dimensional inspection. Core inspection items include: XRD verification of crystal orientation deviation, wafer-wide size and thickness uniformity inspection, flatness and parallelism interference testing, surface roughness and defect screening, full visual defect inspection, transmittance sampling inspection and cleanliness testing. A complete Certificate of Analysis (COA) can be provided for all grades of products. Semiconductor-grade products strictly follow clean packaging specifications, ensuring accurate product parameters and stable performance to meet the stringent requirements of high-end industrial and scientific research scenarios.

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