GaN Light-Emitting Element Gentle Slope Electrode Formation
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Solution Overview
Problem
The existing GaN semiconductor light-emitting elements with large inclination angles, such as 61.9 degrees, make it difficult to form electrodes using photolithographic methods like lift-off due to the challenging geometry.
Innovation Solution
A GaN semiconductor light-emitting element with a seed region having a top face as the A plane and an underlying layer with gentle inclination angles, specifically between 40.2 degrees ± 5 degrees for the S plane, allowing for easier electrode formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the underlying layer is formed with a large inclination angle (61.9 degrees) as in conventional designs, then the crystal growth orientation is improved, but the ease of electrode formation deteriorates
Solution Approach 1:
The invention changes the inclination angle parameter of the underlying layer from the conventional 61.9 degrees to a smaller angle (0-45 degrees), specifically using the S plane orientation. This parameter change allows the crystal growth orientation to be maintained while creating a gentler slope that is suitable for photolithographic electrode formation processes.
Solution Approach 2:
The invention introduces a new dimensional approach by specifying the crystal plane orientation (S plane) rather than just the inclination angle. This dimensional change in describing the geometry allows for both gentle slopes and proper crystal orientation to coexist, resolving the contradiction between manufacturability and crystal quality.
2Ease of manufacture
If the inclination angle of the underlying layer is reduced to enable easy electrode formation, then the ease of manufacture improves, but the crystal growth orientation may deteriorate
Solution Approach 1:
The invention simultaneously optimizes two parameters: the inclination angle (reduced to 0-45 degrees) and the crystal plane orientation (specified as S plane). This dual parameter optimization ensures that even with a gentler slope, the crystal growth maintains proper orientation, thus improving ease of manufacture without sacrificing reliability.
3Reliability
If a pyramidal or strip-like three-dimensional structure is used, then the light emission characteristics are improved, but the difficulty of electrode formation increases due to large inclination angles
Solution Approach 1:
The invention modifies the geometric parameters of the pyramidal or strip-like structure by reducing the inclination angle of the underlying layer to 0-45 degrees. This parameter change maintains the beneficial three-dimensional light emission characteristics while making the surfaces gentler and more suitable for photolithographic electrode formation.
Solution Approach 2:
The invention specifies the crystal plane orientation (S plane) as an additional dimensional parameter, which allows the three-dimensional structure to maintain its light emission properties while having gentler slopes that facilitate electrode formation, thus resolving the contradiction between performance and manufacturability.
Data Source
AI summary
A GaN semiconductor light-emitting element is provided. The GaN semiconductor light-emitting element includes an island-type seed region composed of a GaN-based compound semiconductor disposed on a substrate; an underlying layer having a three-dimensional shape composed of a GaN-based compound semiconductor, disposed on at least the seed region; a first GaN-based compound semiconductor layer of a first conductivity type, an active layer composed of a GaN-based compound semiconductor, and a second GaN-based compound semiconductor layer of a second conductivity type disposed in that order on the underlying layer; a first electrode electrically connected to the first GaN-based compound semiconductor layer; and a second electrode disposed on the second GaN-based compound semiconductor layer. The top face of the seed region is the A plane, and at least one side face of the underlying layer is the S plane.