Sense Cell Trench Layout for Accurate Main Current Detection
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Solution Overview
Problem
In semiconductor devices with main and sense cell regions, the current ratio between the main and sense cell regions differs from the area ratio due to spreading resistance, leading to decreased detection accuracy of current flowing through the main cell region.
Innovation Solution
The semiconductor device design includes main and sense contact trenches that extend in one direction, with the first impurity region in each region protruding more than the upper electrode, allowing the regions to be arranged closer, thereby reducing current spreading and maintaining the current ratio in line with the area ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the main cell region and sense cell region are arranged with sufficient spacing to avoid interference, then the detection accuracy should improve, but the device area increases and current spreading cannot be effectively suppressed
Solution Approach 1:
The patent transitions from planar arrangement to three-dimensional vertical stacking, where the main cell region and sense cell region are positioned at different heights along the stacking direction. This dimensional change allows the regions to be closely spaced horizontally while maintaining electrical isolation through vertical separation, thus improving detection accuracy without increasing device footprint.
Solution Approach 2:
The patent introduces an insulating film as an intermediary layer between the main cell region and sense cell region. This insulating film prevents direct electrical contact and suppresses current spreading between the two regions, enabling accurate current detection in the sense cell region while maintaining compact device dimensions.
2Area of stationary object
If the main upper electrode and sense upper electrode are positioned close to each other to reduce device area, then the device becomes more compact, but current spreads between the regions causing detection errors
Solution Approach 1:
The patent positions the main upper electrode and sense upper electrode at different vertical levels along the stacking direction, with the insulating film separating them. This vertical separation allows the electrodes to be closely spaced in the horizontal plane while preventing current spreading through the insulating barrier, thus achieving compact device area without sacrificing detection accuracy.
Solution Approach 2:
The insulating film serves as a mediator between the main upper electrode and sense upper electrode, providing electrical isolation while allowing the electrodes to be positioned in close proximity. This enables the device to maintain compact dimensions while preventing harmful current spreading that would otherwise occur between closely spaced electrodes.
3Measurement precision
If the contact trenches and impurity regions are extended further to suppress current spreading, then detection accuracy improves, but the manufacturing complexity increases
Solution Approach 1:
Instead of extending contact trenches and impurity regions further in the horizontal plane, the patent utilizes the vertical dimension by positioning structures at different heights and introducing insulating films between layers. This approach suppresses current spreading effectively while avoiding the need for excessively complex horizontal extensions, thus improving detection accuracy without proportionally increasing manufacturing complexity.
Data Source
AI summary
In a semiconductor device having a main cell region and a sense cell region, a main contact trench and a sense contact trench extend in one direction. When viewed from a stacking direction of a drift layer and a body layer, in the one direction, the main contact trench and a first impurity region disposed in the main cell region protrude more than a main upper electrode toward a sense upper electrode, and the sense contact trench and the first impurity region disposed in the sense cell region protrude more than the sense upper electrode toward the main upper electrode.