LED Electrode Pad Structure for Uniform Current Spreading
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Solution Overview
Problem
Conventional light-emitting diodes face challenges in achieving smaller sizes with qualified photoelectric characteristics and manufacturing yield, especially as they are integrated into smaller optoelectronic products, where current designs may suffer from non-uniform current distribution and stress concentration issues affecting reliability.
Innovation Solution
A light-emitting device design featuring a semiconductor stack with a first and second semiconductor layer, an active region, and a unique insulating stack with specific electrode pad configurations that include platform and depression areas on the contact pads, optimizing the area ratio and acute angles to enhance current spreading and reduce stress, thereby improving light efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light-emitting diode size is reduced, then the device can be integrated into smaller optoelectronic products, but the photoelectric characteristics and manufacturing yield deteriorate
Solution Approach 1:
The electrode pad structure is designed with different local geometries including platform areas and depression areas with specific area ratios (50%-80%), creating localized variations in current distribution. This local quality differentiation allows optimized current spreading in critical regions while maintaining overall device compactness, resolving the contradiction between small size and reliable photoelectric performance
Solution Approach 2:
The invention transitions from a conventional flat electrode pad to a three-dimensional structure with platform and depression areas, utilizing vertical dimension variations to control current flow paths. This dimensional change enables enhanced current spreading efficiency within a compact footprint, allowing reduced device size while maintaining manufacturing yield and photoelectric characteristics
2Stability of the object's composition
If the electrode pad area is increased, then current distribution uniformity improves, but the device size increases
Solution Approach 1:
The electrode pad is segmented into multiple functional areas: platform areas providing current injection zones and depression areas facilitating current spreading. This segmentation allows the same horizontal footprint to achieve enhanced current distribution uniformity through vertical structure variations, improving current uniformity without increasing overall device size
Solution Approach 2:
The depression areas are nested within the overall electrode pad structure, creating a multi-level configuration where smaller functional regions are embedded within the larger pad geometry. This nesting enables complex current distribution patterns within a compact area, achieving uniform current distribution without proportionally increasing device size
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
The design achieves improved light efficiency and reliability by ensuring uniform current distribution and reducing stress concentrations, allowing for smaller, more reliable light-emitting diodes suitable for compact optoelectronic applications.
Implementation Method 1
When light-emitting diode is conducted through the electrode and operates under a specific forward bias, holes from the p-type semiconductor layer and electrons from the n-type semiconductor layer combine in the active layer to emit light
Data Source
AI summary
A light-emitting device includes: a semiconductor stack, including a first semiconductor layer, an active region and a second semiconductor layer; a first contact electrode and a second contact electrode formed on the semiconductor stack, wherein the first contact electrode includes a first contact part formed on the first semiconductor layer and the second contact electrode includes a second contact part formed on the second semiconductor layer; an insulating stack formed on the semiconductor stack, including an opening on the second contact part; a first electrode pad and a second electrode pad formed on the insulating stack, wherein the second electrode pad filled in the opening and connecting the second contact part; wherein the second electrode pad includes an upper surface, and the upper surface includes a platform area and a depression area on the second contact part; wherein the platform area has a maximum height relative to other areas of the upper surface; wherein an area of a projection of the platform area on a horizontal plane is A1, and a sum of areas of the projections of the platform area and the depression area on the horizontal plane is A2, and a ratio of A1/A2 ranges from 50%-80%.