Current Blocking Layer Patterns for Uniform Current Spreading
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Solution Overview
Problem
Semiconductor light emitting devices face challenges in achieving uniform current distribution and enhanced light emission efficiency due to limitations in current spreading effects, particularly when using substrates with electrical insulation or conductive substrates, which affect the utilization of active layers as effective light emitting regions.
Innovation Solution
The implementation of a semiconductor light emitting device structure that includes a current blocking layer with patterns arrayed to have smaller intervals near bonding pads and larger intervals away from them, along with electrode branches and a transparent electrode layer, to facilitate improved current spreading and light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mesa etching process is used to form electrodes on an insulating substrate, then electrode connection is achieved, but light emitting area is reduced and current distribution becomes non-uniform
Solution Approach 1:
The current blocking layer is divided into multiple patterns (first patterns and second patterns) with different intervals, creating segmented current blocking regions that guide current flow while preserving light emitting area. The first patterns are positioned near bonding pads with smaller intervals to block concentrated current, while second patterns extend toward active layer edges with larger intervals to maintain light emission.
Solution Approach 2:
Different regions of the current blocking layer have different pattern intervals tailored to local current distribution characteristics. Regions near bonding pads have smaller intervals to effectively block concentrated current, while regions near active layer edges have larger intervals to preserve light emitting area. This local differentiation optimizes both current control and light emission.
2Loss of energy
If electrode size is reduced to improve light emission, then light loss decreases, but driving voltage increases and current spreading deteriorates
Solution Approach 1:
The current blocking layer acts as an intermediary structure between the bonding pads and the active layer. It mediates current flow by blocking concentrated current paths while guiding current to spread uniformly across the active layer, thereby reducing driving voltage without requiring larger electrode sizes that would cause light loss.
3Productivity
If current spreading effects are increased to improve light emission efficiency, then active layer utilization improves, but device complexity increases
Solution Approach 1:
The current blocking layer extends in multiple dimensions: vertically between the bonding pads and active layer, and horizontally with patterns extending from regions near bonding pads toward active layer edges. This multi-dimensional configuration achieves comprehensive current control and uniform spreading without requiring complex three-dimensional structures or additional layers.
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 configuration enhances current spreading effects and light emission efficiency by dispersing concentrated current uniformly across the active layer, increasing the effective light emitting area and reducing driving voltage.
Implementation Method 1
a current blocking layer between a second conductive semiconductor layer and an ohmic contact layer having a plurality of patterns formed thereon
Data Source
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AI summary
There is provided a semiconductor light emitting device including: a semiconductor light emitting laminate including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer interposed therebetween; a first electrode having at least one bonding pad formed on a portion of an upper surface of the first conductive semiconductor layer; a second electrode having an ohmic contact layer formed on the second conductive semiconductor layer; and a current blocking layer between the second conductive semiconductor layer and the ohmic contact layer having a plurality of patterns formed thereon, the plurality of patterns being arrayed such that intervals between patterns adjacent to a region overlapped with the bonding pad are smaller an interval between patterns of another regions.