2inch 4inch 6inch Patterned Sapphire Substrate (PSS) for Light Emitting Diodes (LEDs)
Patterned sapphire substrate (PSS) is a miniature patterned sapphire substrate. It has been widely used in high-power gallium nitride-based light-emitting diodes (leds), which are the most promising alternative light sources for general lighting. With the breakthrough of pattern-sapphire substrate technology, the efficiency of high-brightness gallium nitride based leds has reached a record high of 150 lm/W. The efficiency improvement of gallium nitride based leds using patterned sapphire substrate technology is usually attributed to the improvement of light extraction efficiency and internal quantum efficiency. The regular pattern produced on the sapphire substrate counterbalances the effect of total internal reflection at the gallium nitride/sapphire interface. Moreover, the internal quantum efficiency is improved due to the possible lateral growth of GaN defilm on the pattern-based sapphire substrate, which reduces thread dislocation.
In summary, GaN epitaxial layers grown on PSS produce epitaxial transverse defects and fewer gap defects between GaN and sapphire substrate. In addition, the lattice parameters of PSS are better matched to GaN, and the epitaxial growth of GaN on PSS results in less dislocation density and refractive index mismatch, thus improving the epitaxial quality.
Patterned sapphire substrate(PSS) Properties
Patterned sapphire substrate(PSS) is a process of making some specific micrometer pattern like Dome,Cone or Pyramid-shaped on the sapphire substrate.Uneven patterns on sapphire substrates can generate light scattering or refraction,thereby improving the luminous efficiency.
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Crystal Structure
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Hexagonal
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Lattice Constant(nm)
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a=4.76Å c=12.99Å
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Density(g/cm3)
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3.98
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Melting point(℃)
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2040
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Mohs Hardness(mohs)
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9
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Dielectric Constant
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9.3(A plane) 11.5(C plane)
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Thermal Conductivity(W/cm.K)
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0.46
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Thermal Expansion
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6.7*10-6/k(C plane) 5.0*10-6/k(A plane)
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Refractive Index
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1.762-1.777
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Transmission
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Test sample:Sapphire:D76.2*4mm
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UV:200~380nm 74%~84%
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Visible light:380~760nm 85%
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Infrared:760~1000nm 85%
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Far-Infrared:>1000nm 80%~100%
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Patterned sapphire substrate(PSS) Parameters
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Item
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Patterned Sapphire Substrate(2~6inch)
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Diameter
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50.8 ± 0.1 mm
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100.0 ± 0.2 mm
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150.0 ± 0.3 mm
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Thickness
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430 ± 25μm
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650 ± 25μm
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1000 ± 25μm
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Surface Orientation
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C-plane (0001) off-angle toward M-axis (10-10) 0.2 ± 0.1°
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C-plane (0001) off-angle toward A-axis (11-20) 0 ± 0.1°
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Primary Flat Orientation
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A-Plane (11-20) ± 1.0°
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Primary Flat Length
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16.0 ± 1.0 mm
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30.0 ± 1.0 mm
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47.5 ± 2.0 mm
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R-Plane
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9-o'clock
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Front Surface Finish
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Patterned
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Back Surface Finish
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SSP:Fine-ground,Ra=0.8-1.2um; DSP:Epi-polished,Ra<0.3nm
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Laser Mark
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Back side
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TTV
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≤8μm
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≤10μm
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≤20μm
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BOW
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≤10μm
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≤15μm
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≤25μm
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WARP
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≤12μm
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≤20μm
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≤30μm
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Edge Exclusion
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≤2 mm
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Pattern Specification
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Shape Structure
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Dome, Cone,Pyramid
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Pattern Height
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1.6~1.8μm
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Pattern Diameter
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2.75~2.85μm
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Pattern Space
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0.1~0.3μm
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Customization specifications:
* Nanometer patterned sapphire substrate(NPSS).
* Sapphire PSS of various orientations.
Major advantage
1. Improved LED light extraction efficiency: PSS improves LED light extraction efficiency by reducing internal reflection and increasing light output through surface patterns.
2. Improved crystal quality: Patterned surfaces help reduce defects in epitaxial growth and improve crystal quality.
3. Enhanced heat dissipation performance: The patterned structure increases the heat dissipation area and helps to reduce the operating temperature of the LED.
4. Lower costs: Higher light efficiency and yield reduce material waste and lower production costs.
Patterned sapphire substrate(PSS) Application
- LED manufacturing: Widely used in high-brightness leds, such as lighting, backlighting and display screens.
- Laser diodes: Used to manufacture highly efficient laser diodes for communication and medical devices.
- Power electronics: Used to manufacture efficient power electronics such as GAN-based HEMTs.
- Optoelectronic devices: used to manufacture efficient light detectors, solar cells and other optoelectronic devices.
Patterned sapphire substrate(PSS) Display
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