Translucent Electrode Thickness Gradient for LED Current Uniformity
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Solution Overview
Problem
Conventional semiconductor elements face challenges in preventing electrode peeling during wire bonding and operation, leading to uneven light emission and increased driving voltage due to the trade-off between film thickness and sheet resistance.
Innovation Solution
A semiconductor element design featuring a translucent electrode with a recessed part for the pad electrode, where the thickness of the bottom surface of the recessed part is between 0% and 70% of the electrode's thickness, along with a gap between the pad electrode and the translucent electrode, and a translucency film with a lower refractive index to enhance light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the film thickness of the translucent electrode is made thinner to prevent peeling, then adhesiveness is improved, but sheet resistance becomes higher causing uneven current diffusion
Solution Approach 1:
The translucent electrode is designed with non-uniform thickness: the bottom surface has thickness of more than 0% and equal to or less than 70% of the top surface thickness. This local variation allows the bottom portion to have better adhesiveness (thinner) while the top portion maintains low sheet resistance (thicker), resolving the contradiction between preventing peeling and ensuring current diffusion.
2Reliability
If the film thickness of the translucent electrode is made thinner to prevent peeling, then peeling resistance is improved, but driving voltage increases due to higher sheet resistance
Solution Approach 1:
By making the bottom surface thickness equal to or less than 70% of the top surface thickness, the electrode achieves better peeling resistance at the interface while maintaining adequate thickness at the top to control sheet resistance and driving voltage.
Solution Approach 2:
The invention changes the thickness parameter of the translucent electrode from uniform to non-uniform distribution, with the bottom surface being thinner (more than 0% and equal to or less than 70% of top surface thickness). This parameter variation simultaneously improves peeling resistance and controls sheet resistance to maintain acceptable driving voltage.
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 design prevents electrode peeling, achieves even luminance intensity, and reduces driving voltage by ensuring low sheet resistance and efficient light transmission.
Implementation Method 1
a translucent electrode which is formed on the p-type nitride semiconductor layer 40 for evenly diffusing current
Implementation Method 2
it is possible to suppress light from being absorbed by the side surface of the pad electrode
Data Source
AI summary
There is provided a semiconductor element including a semiconductor layer, a translucent electrode which is formed on the semiconductor layer, and a pad electrode which is formed on the translucent electrode, wherein the translucent electrode includes a recessed part on which the pad electrode is mounted, and wherein a thickness of a bottom surface of the recessed part of the translucent electrode is more than 0% of and equal to or less than 70% of a thickness of a part of the translucent electrode other than the recessed part.