Recessed Electrode Layout for UV LED Current Spreading
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Solution Overview
Problem
Semiconductor devices using aluminum compositions face challenges with current dispersion efficiency and light emitting efficiency at side surfaces, particularly in ultraviolet wavelength bands, leading to reduced emission intensity and non-uniformity.
Innovation Solution
The semiconductor device incorporates a structure with a first and second conductive semiconductor layer, an active layer, and recesses that extend through the second conductive semiconductor layer and active layer to the first conductive semiconductor layer, featuring a higher number of first recesses with smaller areas and fewer second recesses with larger areas, optimized to improve current dispersion and emission uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If aluminum composition is increased to generate ultraviolet light, then light emitting capability is improved, but current dispersion efficiency is lowered
Solution Approach 1:
The semiconductor device divides the contact structure into multiple discrete contact holes arranged in an array pattern, rather than using a single large contact. This segmentation allows current to disperse through multiple pathways into the active layer, improving current dispersion efficiency while maintaining the aluminum composition needed for ultraviolet light emission.
Solution Approach 2:
The patent applies different aluminum composition ratios in different regions of the semiconductor structure. The light-emitting layer has a specific aluminum composition optimized for ultraviolet emission, while the contact structure and other layers have compositions optimized for electrical conductivity and current dispersion, allowing each region to have locally optimized properties.
2Illumination intensity
If aluminum composition is increased for ultraviolet emission, then light output is improved, but emission uniformity deteriorates
Solution Approach 1:
The array of multiple contact holes creates a uniform distribution of current injection points across the light-emitting layer. This segmented contact structure ensures that current is injected uniformly throughout the active region, producing uniform light emission across the entire device area, even with high aluminum composition.
Solution Approach 2:
The contact holes are designed with specific asymmetric dimensional relationships - the first dimension (width) is larger than the second dimension (length), and the spacing between contacts is optimized in specific directions. This asymmetric geometry optimizes current dispersion patterns to achieve uniform emission across the rectangular light-emitting area.
Data Source
AI summary
An embodiment provides a semiconductor device comprising: a semiconductor structure including a first conductive semiconductor layer, an active layer, a second conductive semiconductor layer, and a plurality of first recesses and second recesses which extend through the second conductive semiconductor layer and the active layer and are arranged up to one region of the first conductive semiconductor layer, a first electrode disposed inside each of the first recesses and second recesses to be electrically connected to the first conductive semiconductor layer, and a second electrode electrically connected to the second conductive semiconductor layer, wherein the first conductive semiconductor layer, the active layer, the second conductive semiconductor layer include aluminum, and the number of most adjacent recesses in the plurality of second recesses is fewer than that in the plurality of first recesses and the plurality of second recesses include multiple recesses, each having an area larger than that of each of the plurality of first recesses.