Semiconductor Light Emitting Element Electrode Joining
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Solution Overview
Problem
The semiconductor light emitting element faces issues with the p pad electrode peeling from the transparent electrode during wire bonding, leading to weak joining properties and deterioration of electrical characteristics, particularly due to the common structure of p and n pad electrodes which complicates ohmic contact formation.
Innovation Solution
A semiconductor light emitting element with a first and second semiconductor layer of different conductivity types, a transparent electrode made of indium oxide, and joining layers composed of Pt and nitride metals like Ta, Nb, Ti, W, or Mo, along with diffusion barrier layers and adhesive layers to enhance the joining and electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common structure (Au and Cr laminated structure) is used for both p pad electrode and n pad electrode, then the configuration is simplified, but the joining property of the p pad electrode with the transparent electrode becomes weak and peeling occurs after wire bonding
Solution Approach 1:
The patent applies different material compositions to different locations of the electrode structure. The p pad electrode uses a specific laminated structure with Au, Cr, and transparent electrode layers, while the n pad electrode uses a different structure optimized for ohmic contact with the n-type semiconductor layer. This local differentiation resolves the contradiction by allowing each electrode to have optimal properties for its specific function and location.
Solution Approach 2:
The patent employs composite material structures for the pad electrodes, combining multiple materials (Au, Cr, and transparent electrode materials) in specific laminated configurations. The p pad electrode uses a composite structure that provides both mechanical strength for wire bonding and electrical conductivity, while the n pad electrode uses a composite structure optimized for ohmic contact formation.
2Ease of manufacture
If a common structure (Au and Cr laminated structure) is used for both p pad electrode and n pad electrode, then manufacturing is simplified, but ohmic contact formation at the n-type semiconductor layer connection becomes difficult and electrical characteristics deteriorate
Solution Approach 1:
The patent implements location-specific electrode structures where the n pad electrode is specifically designed with materials and configurations optimized for ohmic contact with the n-type semiconductor layer, while the p pad electrode is designed for the p-type layer. This local optimization ensures that each electrode achieves its required electrical characteristics without compromising manufacturing feasibility.
Solution Approach 2:
The patent changes the material composition and structural parameters of the electrodes based on their specific locations and functions. The n pad electrode uses a structure with parameters optimized for low-resistance ohmic contact, while the p pad electrode uses parameters optimized for wire bonding attachment and transparency.
Data Source
AI summary
A semiconductor light emitting element (1) provided with an n-type semiconductor layer (140), a light emitting layer (150), a p-type semiconductor layer (160), a transparent electrode (170), a p-side electrode (300) formed on the transparent electrode, and an n-side electrode (400) formed on the n-type semiconductor layer. The p-side electrode has a p-side joining layer (310) and a p-side bonding pad electrode (320), which are laminated on the transparent electrode, and the n-side electrode has an n-side joining layer (410) and an n-side bonding pad electrode (420), which are laminated on the n-type semiconductor layer. The p-side joining layer and the n-side joining layer are configured of a mixed layer composed of TaN and Pt, and the p-side bonding pad electrode and the n-side bonding pad electrode are configured of a laminated structure composed of Pt and Au.