SiC Backside Raised Portions for Larger Electrode Ohmic Contact
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Solution Overview
Problem
Existing semiconductor devices with SiC substrates face challenges in improving electrical characteristics due to limited connection areas between electrodes and the substrate, leading to suboptimal performance.
Innovation Solution
A semiconductor device design featuring an SiC semiconductor layer with a raised portion group on the second main surface, where the raised portions overlap in specific patterns to increase the electrode connection area, enhancing electrical characteristics by forming an ohmic contact without relying on carbon or silicide layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional flat electrode structure is used on the SiC substrate, then the manufacturing process is simple, but the connection area between electrode and substrate is limited, resulting in poor electrical characteristics
Solution Approach 1:
The invention transitions from a two-dimensional flat electrode structure to a three-dimensional raised portion structure. By forming multiple raised portions that protrude from the substrate surface, the electrode connection area is significantly increased in the vertical dimension, thereby improving electrical characteristics without expanding the planar footprint.
Solution Approach 2:
The electrode structure is segmented into multiple discrete raised portions rather than a continuous flat layer. These raised portions are distributed across the substrate surface, each providing a localized high-contact-area region that collectively enhances the overall connection area and electrical performance.
2Reliability
If the electrode connection area is increased to improve electrical characteristics, then resistance values decrease, but the device structure becomes more complex
Solution Approach 1:
Instead of increasing connection area through planar expansion, the invention utilizes the vertical dimension by creating raised portions that protrude from the substrate. This three-dimensional approach achieves larger connection area with minimal additional horizontal space, thereby limiting structural complexity.
Solution Approach 2:
The raised portions are formed with curved or rounded surfaces rather than sharp geometric features. This curvature simplifies the manufacturing process (particularly laser processing) and reduces structural complexity while still providing increased surface area for electrode contact.
Data Source
AI summary
A semiconductor device includes an SiC semiconductor layer which has a first main surface on one side and a second main surface on the other side, a semiconductor element which is formed in the first main surface, a raised portion group which includes a plurality of raised portions formed at intervals from each other at the second main surface and has a first portion in which some of the raised portions among the plurality of raised portions overlap each other in a first direction view as viewed in a first direction which is one of the plane directions of the second main surface, and an electrode which is formed on the second main surface and connected to the raised portion group.