Nitride Light Emitting Element Layout for Current Leakage Reduction
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Solution Overview
Problem
Current methods for manufacturing light emitting elements using semiconductor wafers often result in significant current leakage due to dust adherence and damage from laser beam irradiation, particularly at the corners of recessed portions, leading to reduced emission area and increased forward voltage.
Innovation Solution
A method involving the formation of a protective layer on the p-side nitride semiconductor layer in regions where light emitting elements will be divided, followed by annealing to reduce resistance in unprotected areas, and laser beam irradiation to create modified regions, which reduces the likelihood of current leakage by maintaining high resistance at the dividing lines and eliminating corners, thereby increasing emission area and reducing forward voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is formed on the p-side nitride semiconductor layer in regions that include borders of areas to become light emitting elements, then current leakage is reduced, but manufacturing process complexity increases
Solution Approach 1:
A protective layer is formed on the p-side nitride semiconductor layer in regions that include borders of areas to become light emitting elements before laser beam irradiation. This preliminary protective action prevents dust adherence and laser damage at critical border regions, reducing current leakage while maintaining a systematic manufacturing process
Solution Approach 2:
The protective layer is selectively formed only in regions that include borders of areas to become light emitting elements, not across the entire semiconductor layer. This localized application reduces manufacturing complexity while providing targeted protection where current leakage is most problematic
2Area of moving object
If the semiconductor wafer is annealed to reduce resistance in areas where no protective layer has been formed, then emission area increases, but manufacturing process complexity increases
Solution Approach 1:
Annealing is performed after protective layer formation to reduce resistance in the semiconductor layer at emission areas. This preliminary resistance reduction enables better current distribution and increases effective emission area before the final dividing process
Solution Approach 2:
The annealing process selectively reduces resistance only in areas where no protective layer has been formed, creating local electrical property variations that optimize current distribution across the semiconductor wafer while maintaining protection at border regions
3Manufacturing precision
If laser beam is irradiated on the substrate to form modified regions, then dividing precision is improved, but current leakage increases due to corner damage
Solution Approach 1:
The protective layer is formed on the p-side nitride semiconductor layer before laser beam irradiation. This preliminary protection prevents laser-induced damage and dust adherence at border regions, eliminating corner damage that causes current leakage while maintaining precise wafer dividing
Solution Approach 2:
The protective layer acts as an intermediary barrier between the laser beam and the p-side nitride semiconductor layer at border regions. It absorbs or deflects laser energy that would otherwise cause damage, while allowing the laser to still form modified regions in the substrate for precise dividing
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 approach significantly reduces current leakage, increases the emission area per semiconductor wafer, and enhances the production yield by minimizing damage from laser irradiation, resulting in more efficient light emitting elements with lower forward voltage.
Implementation Method 1
forming a protective layer on an upper face of the p-side nitride semiconductor layer in regions that include borders of areas to become the plurality of light emitting elements
Implementation Method 2
reducing a resistance of the p-side nitride semiconductor in areas where no protective layer has been formed by annealing the semiconductor wafer
Implementation Method 3
irradiating a laser beam on the substrate so as to form modified regions in the substrate
Data Source
AI summary
A light emitting element includes: a semiconductor structure including: a substrate, an n-side nitride semiconductor layer located on the substrate, and a p-side nitride semiconductor layer located on the n-side nitride semiconductor layer, wherein a p-side nitride semiconductor side of the semiconductor structure is a light extraction face side, and an n-side nitride semiconductor side of the semiconductor structure is a mounting face side; a first protective layer located on and in direct contact with an upper face of the p-side nitride semiconductor layer in a region corresponding to the peripheral portion of the p-side nitride semiconductor layer; and a current diffusion layer located on and in direct contact with an upper face of the p-side nitride semiconductor layer in a region corresponding to the area inside of the peripheral portion. The current diffusion layer does not overlap the first protective layer in a top view.