Current Spreading Layer Layout for Uniform LED Chip Emission
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Solution Overview
Problem
Optoelectronic semiconductor devices face challenges in achieving homogeneous current distribution and heat dissipation, leading to inhomogeneous luminance and potential degradation due to varying current densities and thermal conductivity across the chip.
Innovation Solution
The design incorporates a first and second current spreading layer with distinct electrical contact elements, where the resistance values of these contact elements are set to satisfy a specific relationship, ensuring uniform energization and reducing temperature gradients, and the use of a heat-dissipating carrier with varying thermal conductivity to manage current flow and heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional LED structures are used with standard electrical contacts, then device simplicity is maintained, but inhomogeneous current distribution and luminance occur
Solution Approach 1:
The patent applies local quality by differentiating the electrical contact elements into at least two types with different resistance values. First electrical contact elements have a first resistance value, while second electrical contact elements have a second resistance value that differs from the first. This local variation in electrical properties allows compensation for position-dependent current density variations, achieving homogeneous current distribution across the active zones without requiring complex overall device restructuring.
Solution Approach 2:
The patent implements parameter changes by varying the resistance value parameter of different electrical contact elements. By setting different resistance values for different contact elements based on their positions relative to the light extraction surface, the patent compensates for non-uniform current distribution. This parameter variation allows each contact element to deliver appropriate current to its associated active zone, achieving uniform luminance output.
2Reliability
If electrical contact elements are positioned closer to the light extraction surface for better connection, then electrical connectivity is improved, but current density becomes non-uniform across active zones
Solution Approach 1:
The patent applies local quality by assigning different resistance values to contact elements based on their specific positions. Contact elements closer to the light extraction surface (which would naturally draw more current) are given higher resistance values, while those farther away receive lower resistance values. This localized adaptation of electrical properties compensates for the positional advantage in electrical connectivity, balancing the current distribution across all active zones.
Solution Approach 2:
The patent introduces asymmetry by deliberately creating unequal resistance values among symmetrically positioned contact elements. Instead of using identical contact elements throughout, the design employs asymmetric resistance values that correspond to the symmetric positions relative to the light extraction surface. This asymmetric parameter assignment counteracts the symmetric geometric advantage, achieving uniform current distribution.
3Ease of manufacture
If uniform electrical contacts are used across the chip, then manufacturing is simplified, but temperature gradients and degradation occur due to inhomogeneous heat generation
Solution Approach 1:
The patent applies local quality by varying the resistance values of electrical contact elements according to their positions relative to the light extraction surface. This creates local differences in power dissipation (P=I²R) that compensate for the non-uniform current distribution. Contact elements closer to the light extraction surface, which would generate more heat due to higher current density, are assigned higher resistance values to reduce their current and heat generation, thereby achieving more uniform thermal distribution across the chip.
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 results in more homogeneous light emission, reduced degradation, and increased efficiency by ensuring uniform current distribution and heat dissipation across the optoelectronic semiconductor device.
Implementation Method 1
The plurality of electrical contact elements is suitable for electrically connecting the first semiconductor layer to the first current spreading layer
Implementation Method 2
the first electrical contact element is connected to an associated active zone via a first resistance value, and the second electrical contact element is connected to an associated active zone via a second resistance value
Implementation Method 3
The first current spreading layer is arranged on a side of the second semiconductor layer facing away from the first semiconductor layer. The second current spreading layer is electrically connected to the second semiconductor layer
Implementation Method 4
When electrons and holes recombine with one another in the area of the pn junction, for example, because a corresponding voltage is applied, electromagnetic radiation is generated
Implementation Method 5
the use of a heat-dissipating carrier with varying thermal conductivity to manage current flow and heat distribution
Data Source
AI summary
An optoelectronic device may include an optoelectronic semiconductor chip that is configured to emit electromagnetic radiation. The chip may include a first semiconductor layer, a second semiconductor layer, first and second current spreading structures, and a plurality of electrical contact elements. The first current spreading layer may be arranged on a side of the second semiconductor layer facing away from the first semiconductor layer. The plurality of electrical contact elements may electrically connect the first semiconductor layer to the first current spreading layer. The second current spreading layer may be electrically connected to the second semiconductor layer. The second current spreading layer may be arranged between the first current spreading layer and the second semiconductor layer where an insulating layer insulates a first electrical contact element and a second electrical contact element from the second current spreading layer.