SiC Semiconductor Electrode Tapered Concave Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices using SiC substrates face issues with electrode exfoliation due to stress from temperature changes during switching operations, leading to reliability concerns and connection failures.
Innovation Solution
The design incorporates a semiconductor layer with a tapered concave portion on the upper surface of the electrode, increasing the contact area and reducing stress, thereby maintaining a stable connection between electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a nickel film is formed on the electrode layer to enable soldering, then soldering capability is improved, but the nickel film may exfoliate due to stress from temperature changes during switching operations
Solution Approach 1:
The invention introduces a concave portion with a curved bottom surface into the electrode layer. This curvature design increases the contact area between the nickel film and the electrode layer, allowing stress to be distributed more evenly. The curved surface enables the nickel film to conform better to the underlying structure, preventing exfoliation while maintaining soldering capability.
Solution Approach 2:
The invention transitions from a flat two-dimensional electrode surface to a three-dimensional structure with a concave portion. By adding vertical depth and creating a recessed area, the design increases the effective contact area without expanding the planar footprint. This dimensional change allows the nickel film to be anchored more securely within the concave region, resisting stress-induced exfoliation.
2Reliability
If the contact area between electrodes is increased to reduce stress, then reliability is improved, but the device structure becomes more complex
Solution Approach 1:
The invention applies the concave portion only in specific regions where stress concentration occurs, rather than making the entire electrode structure complex. The concave portion is strategically positioned to provide localized stress relief and enhanced contact area where needed, while maintaining simple flat structures in other areas. This selective application of complexity optimizes reliability without unnecessarily increasing overall device complexity.
Data Source
AI summary
Even when a stress is applied due to energization or switching operation, a connection state of electrode layers can be appropriately maintained. A semiconductor device includes a semiconductor layer of first conductivity type, an upper surface structure formed on a surface layer of the semiconductor layer, and an upper surface electrode formed over the upper surface structure. The upper surface electrode includes a first electrode formed on an upper surface of the semiconductor layer, and a second electrode formed over an upper surface of the first electrode. The first concave portion is formed on the upper surface of the first electrode. A side surface of the first concave portion has a tapered shape. The second electrode is formed over the upper surface of the first electrode including an inside of the first concave portion.