Trench Source Electrode Layout for Low-Resistance Semiconductor Switching
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Solution Overview
Problem
Current semiconductor devices face challenges in regulating source resistance and preventing voltage concentration and leakage current due to high source resistance, leading to decreased breakdown voltage and increased leakage current in switching circuits.
Innovation Solution
The semiconductor device incorporates a second trench structure with a shorter current path and adjusted source electrode projection lengths, along with a trench connection structure, to reduce source resistance and prevent voltage concentration, allowing for wider depletion layers and improved breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the source electrode is arranged at the bottom of the trench, then the current path is lengthened, but the source resistance increases and voltage concentration occurs
Solution Approach 1:
The source electrode is extended laterally along the bottom of the trench in the third direction (width direction), transforming a point-like contact into a line-like contact. This dimensional change increases the effective contact area without increasing the trench depth, thereby reducing source resistance while maintaining the bottom-positioned configuration that enables wide depletion layers.
Solution Approach 2:
The source electrode is positioned specifically at the bottom region of the trench rather than spanning the entire trench height, creating a localized contact region. This local positioning optimizes the depletion layer formation at the critical bottom region where voltage concentration would otherwise occur, while the lateral extension provides sufficient contact area to reduce resistance.
2Object-generated harmful factors
If the source electrode projection length is increased, then the contact area is increased, but the device width is increased
Solution Approach 1:
The source electrode utilizes the third dimension (width/depth direction along the trench bottom) to increase contact area, rather than extending in the lateral plane. This allows the electrode to achieve sufficient contact length for low resistance while maintaining a compact planar footprint, thus reducing source resistance without proportionally increasing device width.
3Reliability
If the trench depth is increased, then the depletion layer is widened, but the manufacturing complexity is increased
Solution Approach 1:
The optimal trench depth is determined as a specific parameter range (e.g., 0.5-2.0 times the channel length) that balances depletion layer width with manufacturing feasibility. By establishing this quantitative relationship, the design transforms the qualitative trade-off into a quantifiable parameter optimization, allowing standard fabrication processes to achieve the required performance without excessive complexity.
Data Source
AI summary
A semiconductor device includes a chip having a main surface, a groove structure including a groove formed at the main surface, a source electrode that is embedded in the groove at a bottom side of the groove and that has a projection portion on one side and a projection portion on the other side both of which protrude toward an opening side of the groove, and a gate electrode embedded between a pair of the projection portions at the opening side of the groove, and a source via electrode on one side and a source via electrode on the other side that are connected to the projection portion on the one side and the projection portion on the other side, respectively, on the groove structure.