Rh P-Side Electrode Interface for Anti-Exfoliation LED Protection
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Solution Overview
Problem
The intimacy of contact between platinum group metals like Rh and insulative films in semiconductor light-emitting elements is poor, leading to easy exfoliation of the insulative film and reduced reliability of the light-emitting element.
Innovation Solution
A semiconductor light-emitting element is designed with a p-side electrode covering layer made of Ti or TiN between the p-side contact electrode made of Rh and the first protective layer, enhancing the contact intimacy and preventing exfoliation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulative film is formed directly on the surface of the p-side electrode made of Rh, then the insulative film provides electrical insulation, but the intimacy of contact between the insulative film and the p-side electrode is poor, leading to easy exfoliation
Solution Approach 1:
A Ti or TiN covering layer is introduced as an intermediary between the Rh p-side contact electrode and the insulative film (SiO2 or SiON). This covering layer serves as a mediator that improves the intimacy of contact and adhesion between the two materials, preventing exfoliation while maintaining electrical insulation functionality.
Solution Approach 2:
The electrode structure is designed as a composite multi-layer system consisting of Rh p-side contact electrode + Ti/TiN covering layer + insulative film. This composite structure combines the advantages of each material: Rh provides electrical conductivity and contact properties, Ti/TiN provides intermediate adhesion and intimacy of contact, and the insulative film provides electrical insulation.
2Reliability
If a protective layer is formed directly on the p-side contact electrode, then the protective layer provides sealing and protection, but the protective layer easily exfoliates due to poor contact intimacy
Solution Approach 1:
The Ti or TiN covering layer acts as an intermediary that ensures stable structural bonding between the Rh p-side contact electrode and the protective insulative layer. This intermediate layer prevents structural instability and exfoliation by improving the intimacy of contact at the interface.
3Reliability
If Rh is used as the p-side electrode material, then the electrode provides good electrical contact with the p-type semiconductor layer, but the intimacy of contact with insulative films is poor
Solution Approach 1:
The Ti or TiN covering layer serves as an intermediary that bridges the Rh electrode and the insulative film interface. This intermediate layer improves the interface quality and intimacy of contact without compromising the electrical contact properties of the Rh electrode with the p-type semiconductor layer.
Data Source
AI summary
A semiconductor light-emitting element includes: an n-type semiconductor layer; an active layer; a p-side contact electrode made of Rh; a p-side electrode covering layer made of Ti or TiN that covers the p-side contact electrode; a first protective layer made of SiO2 or SiON that covers an upper surface and a side surface of the p-side electrode covering layer in a portion different from that of a first p-side pad opening; a second protective layer made of Al2O3 that covers the first protective layer, a side surface of a p-side semiconductor layer, and a side surface of the active layer in a portion different from that of a second p-side pad opening; and a p-side pad electrode that is in contact with the p-side electrode covering layer in the first p-side pad opening and the second p-side pad opening.