A sapphire wafer is a thin slice of crystalline sapphire, a material that is widely known for its exceptional hardness and transparency. Sapphire, or aluminum oxide (Al₂O₃), is a crystalline form of corundum, and in its purest form, it is colorless and transparent. Sapphire wafers are extensively used in the electronics and optoelectronics industries, especially in applications that require a durable, high-performance substrate material.
| tandard wafer(customzied)2 inch C-plane sapphire wafer SSP/DSP 3 inch C-plane sapphire wafer SSP/DSP 4 inch C-plane sapphire wafer SSP/DSP 6 inch C-plane sapphire wafer SSP/DSP |
Special Cut A-plane (1120) sapphire wafer R-plane (1102) sapphire wafer M-plane (1010) sapphire wafer N-plane (1123) sapphire wafer C-axis with a 0.5°~ 4° offcut, toward A-axis or M-axis Other customized orientation |
| Customized Size 10*10mm sapphire wafer 20*20mm sapphire wafer Ultra thin (100um) sapphire wafer 8 inch sapphire wafer |
Patterned Sapphire Substrate (PSS) 2 inch C-plane PSS 4 inch C-plane PSS |
| 2inch | DSP C-AXIS 0.1mm/0.175mm/0.2mm/0.3mm/0.4mm/0.5mm/ 1.0mmt SSP C-axis 0.2/0.43mm(DSP＆SSP) A-axis/M-axis/R-axis 0.43mm |
| 3inch | DSP/ SSP C-axis 0.43mm/0.5mm |
| 4Inch | dsp c-axis 0.4mm/ 0.5mm/1.0mmssp c-axis 0.5mm/0.65mm/1.0mmt |
| 6inch | ssp c-axis 1.0mm/1.3mmm dsp c-axis 0.65mm/ 0.8mm/1.0mmt |
Specification for substrates
| Orientation | R-plane, C-plane, A-plane, M-plane or a specified orientation |
| Orientation Tolerance | ± 0.1° |
| Diameter | 2 inches, 3 inches, 4 inches, 5inch,6 inches, 8 inches or others |
| Diameter Tolerance | 0.1mm for 2 inches, 0.2mm for 3 inches, 0.3mm for 4 inches, 0.5mm for 6 inches |
| Thickness | 0.08mm,0.1mm,0.175mm,0.25mm, 0.33mm, 0.43mm, 0.65mm, 1mm or others; |
| Thickness Tolerance | 5μm |
| Primary Flat Length | 16.0±1.0mm for 2 inches, 22.0±1.0mm for 3 inches, 30.0±1.5mm for 4 inches, 47.5/50.0±2.0mm for 6 inches |
| Primary Flat Orientation | A-plane (1 1-2 0 ) ± 0.2°; C-plane (0 0-0 1 ) ± 0.2°, Projected C-Axis 45 +/- 2° |
| TTV | ≤7µm for 2 inches, ≤10µm for 3 inches, ≤15µm for 4 inches, ≤25µm for 6 inches |
| BOW | ≤7µm for 2 inches, ≤10µm for 3 inches, ≤15µm for 4 inches, ≤25µm for 6 inches |
| Front Surface | Epi-Polished (Ra< 0.3nm for C-plane, 0.5nm for other orientations) |
| Back Surface | Fine ground (Ra=0.6μm~1.4μm) or Epi-polished |
| Packaging | Packaged in a class 100 clean room environment |
Sapphire wafers are manufactured through a process called the Czochralski method (or the Kyropoulos method), where large single-crystal sapphire boules are grown from molten aluminum oxide. These boules are then sliced into wafers of the desired thickness using a diamond wire saw. After slicing, the wafers undergo polishing to achieve a smooth, mirror-like surface.
Hardness: Sapphire ranks 9 on the Mohs scale of mineral hardness, making it the second-hardest material after diamond. This exceptional hardness makes sapphire wafers highly resistant to scratching and mechanical damage.
Thermal Stability: Sapphire can withstand high temperatures, with a melting point of about 2,030°C (3,686°F). This makes it ideal for high-temperature applications where other materials might fail.
Optical Transparency: Sapphire is highly transparent to a wide range of wavelengths, including visible, ultraviolet (UV), and infrared (IR) light. This property makes sapphire wafers ideal for use in optical devices, windows, and sensors.
Electrical Insulation: Sapphire is an excellent electrical insulator with a high dielectric constant. This makes it suitable for applications where electrical isolation is critical, such as in certain types of microelectronics.
Chemical Resistance: Sapphire is chemically inert and highly resistant to corrosion from acids, bases, and other chemicals, which makes it durable in harsh environments.
Light-Emitting Diodes (LEDs): Sapphire wafers are commonly used as substrates in the manufacturing of gallium nitride (GaN) LEDs, especially blue and white LEDs. The lattice structure of sapphire matches well with GaN, promoting efficient light emission.
Semiconductor Devices: In addition to LEDs, sapphire wafers are used in radio-frequency (RF) devices, power electronics, and other semiconductor applications where a robust and insulating substrate is needed.
Optical Windows and Lenses: Sapphire’s transparency and hardness make it an excellent material for optical windows, lenses, and camera sensor covers, often used in harsh environments such as aerospace and defense industries.
Wearables and Electronics: Sapphire is used as a durable cover material for wearables, smartphone screens, and other consumer electronics, thanks to its scratch resistance and optical clarity.
While sapphire wafers have distinct advantages in certain applications, they are often compared with silicon wafers, which are the most common substrate material in the semiconductor industry.
Silicon wafers are thin slices of crystalline silicon, a semiconductor material. They are the foundation of the modern electronics industry, used in the manufacturing of integrated circuits (ICs), transistors, and solar cells. Silicon wafers are known for their electrical conductivity, and their ability to be doped with impurities to enhance their semiconductor properties.
Electrical Conductivity: Unlike sapphire, silicon is a semiconductor, meaning it can conduct electricity under certain conditions. This property makes silicon ideal for making electronic devices like transistors, diodes, and ICs.
Cost: Silicon wafers are generally less expensive to produce than sapphire wafers. This is because silicon is more abundant in nature, and the processes for silicon wafer manufacturing are more established and efficient.
Thermal Conductivity: Silicon has good thermal conductivity, which is important for dissipating heat in electronic devices. However, it is not as thermally stable as sapphire in extreme temperature environments.
Flexibility in Doping: Silicon can be easily doped with elements like boron or phosphorus to modify its electrical properties, which is a key factor in its widespread use in the semiconductor industry.
| Property | Sapphire Wafer | Silicon Wafer |
|---|---|---|
| Material | Crystalline Aluminum Oxide (Al₂O₃) | Crystalline Silicon (Si) |
| Hardness | 9 on Mohs scale (extremely hard) | 6.5 on Mohs scale |
| Thermal Stability | Extremely high (melting point ~2,030°C) | Moderate (melting point ~1,410°C) |
| Electrical Properties | Insulator (non-conductive) | Semiconductor (conductive) |
| Optical Transparency | Transparent to UV, visible, and IR light | Opaque |
| Cost | Higher | Lower |
| Chemical Resistance | Excellent | Moderate |
| Applications | LEDs, RF devices, optical windows, wearables | ICs, transistors, solar cells |
The choice between sapphire and silicon wafers depends largely on the specific application:
Sapphire Wafers: Ideal for applications requiring extreme durability, high-temperature resistance, optical transparency, and electrical insulation. These are preferred in optoelectronics, particularly in LEDs, and in environments where mechanical strength and chemical resistance are essential.
Silicon Wafers: The go-to choice for general semiconductor applications due to their semiconductor properties, cost-effectiveness, and the well-established manufacturing processes in the electronics industry. Silicon is the backbone of integrated circuits and other electronic devices.
With the growing demand for more durable and high-performance materials in electronics, optoelectronics, and wearables, sapphire wafers are expected to play an increasingly important role. Their unique combination of hardness, thermal stability, and transparency makes them suitable for cutting-edge technologies, including next-generation displays, advanced semiconductor devices, and robust optical sensors.
As the cost of sapphire wafer production decreases and the manufacturing processes improve, we can anticipate their wider adoption across industries, further solidifying their place as a critical material in modern technology.
