Semiconductor Light-Emitting Device with Stripe Grooves
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Solution Overview
Problem
Group III nitride-based compound semiconductor light-emitting devices face challenges in achieving high light extraction efficiency due to the limitations of groove patterns, which either scatter light in one direction while failing to do so in another, and result in non-uniform crystal orientations when grooves are formed in a lattice pattern.
Innovation Solution
The solution involves forming stripe-patterned grooves on a sapphire substrate with discontinuous dielectrics in one direction and continuous or discontinuous dielectrics in a perpendicular direction, allowing light to be reflected and extracted efficiently, and growing a Group III nitride-based compound semiconductor on the side surfaces of the grooves to achieve a uniform non-polar plane with reduced internal electric field, enhancing light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If grooves are formed in a stripe pattern to scatter light in one direction, then light extraction efficiency is improved in that direction, but light propagating in the perpendicular direction is reflected and guided by sidewalls without scattering
Solution Approach 1:
The invention transitions from a one-dimensional stripe pattern to a two-dimensional lattice pattern of grooves. This dimensional change enables light scattering in multiple directions simultaneously, resolving the directional limitation of stripe patterns while maintaining the light extraction enhancement mechanism.
Solution Approach 2:
The invention divides the substrate surface into multiple regions with grooves arranged in a lattice pattern, creating multiple scattering centers. This segmentation allows light to be scattered in various directions through different groove elements, achieving omnidirectional light extraction improvement.
2Illumination intensity
If grooves are formed in a lattice pattern to improve light scattering, then light extraction efficiency is improved, but plane orientation differs among sidewalls leading to non-uniform semiconductor layer
Solution Approach 1:
The invention applies different properties to different parts of the structure: the grooves have specific orientations that differ from location to location in the lattice pattern, but the semiconductor layer growth is controlled to achieve uniformity through careful process design, allowing local variations in groove orientation while maintaining overall layer uniformity.
3Ease of manufacture
If grooves are formed in a stripe pattern, then manufacturing is simpler, but light propagating in stripe direction passes through convexes and concaves without scattering
Solution Approach 1:
The invention enhances the manufacturing process by adding a second dimension to the groove pattern (forming a lattice instead of simple stripes). This additional dimensional complexity is achieved through standard photolithography and etching processes, maintaining ease of manufacture while dramatically improving light extraction efficiency through multi-directional scattering.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly improves external light extraction efficiency by ensuring light is scattered and reflected in the desired direction, maintaining high light emission efficiency while preventing wavelength shifts, and allows for uniform crystal orientation on non-polar planes.
Implementation Method 1
a light propagating in a direction perpendicular to the stripe direction on the substrate is scattered on an embossed surface
Implementation Method 2
a light component propagating in the stripe direction passes through the convexes and the concaves, and is reflected and guided by the sidewalls of the grooves
Implementation Method 3
Semiconductor light-emitting device wherein each layer is made of a Group III nitride-based compound semiconductor
Data Source
AI summary
To improve light extraction efficiency.A semiconductor light-emitting device wherein each layer is formed of a Group III nitride-based compound semiconductor. The light-emitting device comprises a sapphire substrate having a plurality of stripe-patterned grooves 11 arranged in parallel to a first direction (x axis) on a surface of the substrate 10, a dielectric 15 discontinuously formed at least in the first direction on the surface 10a of the sapphire substrate and in the grooves 11, a base layer being grown on side surfaces of the grooves and made of a Group III nitride-based compound semiconductor covering the surface 10a of the sapphire substrate and the top surfaces 15a of the dielectrics 15, and a device layer constituting a light-emitting device formed on the base layer.