LED Mesa Surface Roughening to Prevent Current Leakage
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) face issues with current leakage due to impurities remaining on side walls during surface roughening, which affects their luminous intensity and efficiency.
Innovation Solution
A light-emitting device with a semiconductor epitaxial structure featuring a first mesa side wall and surface with a roughened connection portion, where the side walls of the active and conductive semiconductor layers are not roughened to prevent current leakage, and a method involving surface roughening of the conductive semiconductor layer away from the active layer to form mesa surfaces and side walls, enhancing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the side walls of the active layer are roughened to increase light extraction efficiency, then the luminous intensity is improved, but impurities remain on the side walls causing current leakage
Solution Approach 1:
The patent applies local quality by differentiating the surface treatment between different regions: the first mesa surface is roughened to enhance light extraction, while the first mesa side wall remains smooth to prevent current leakage. This selective surface treatment allows each region to have the optimal surface characteristics for its specific function.
Solution Approach 2:
The patent segments the surface treatment into distinct regions: a roughened first mesa surface for light extraction and a smooth first mesa side wall for electrical isolation. This segmentation allows independent optimization of each region's properties without compromising the other.
2Reliability
If the side walls are not roughened to prevent current leakage, then electrical reliability is improved, but the luminous intensity is reduced
Solution Approach 1:
The patent applies local quality by differentiating the surface treatment between different regions: the first mesa surface is roughened to enhance light extraction, while the first mesa side wall remains smooth to prevent current leakage. This selective surface treatment allows each region to have the optimal surface characteristics for its specific function.
Solution Approach 2:
The patent resolves the contradiction by transitioning from a single-surface treatment approach to a multi-surface approach, treating the top surface (first mesa surface) and side surface (first mesa side wall) differently. This dimensional differentiation allows simultaneous optimization of light extraction (top surface) and electrical isolation (side surface).
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 solution effectively increases the luminous intensity and light-emitting efficiency of LEDs by preventing current leakage while maintaining the structural integrity of the device, thereby improving external quantum efficiency.
Implementation Method 1
if light emitted by the LED is unable to be exacted effectively, a portion of the light is then reflected or refracted back and forth inside the LED
Implementation Method 2
if light emitted by the LED is unable to be exacted effectively, a portion of the light is then reflected or refracted back and forth inside the LED
Data Source
AI summary
A light-emitting device includes a semiconductor epitaxial structure that has a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer, a first mesa side wall that is defined by a side wall of the first conductive semiconductor layer and a side wall of the active layer, and a first mesa surface that is defined by a portion of a top surface of the second conductive semiconductor layer. The first mesa side wall has a side wall bottom end connected to the first mesa surface to form a connection portion, which is constituted of the side wall bottom end and a mesa surface proximal region of the first mesa surface that adjoins the side wall bottom end and is roughened. A method for manufacturing the light-emitting device is also disclosed.