Intersecting Trench Power Semiconductor Layout for Lower Switching Loss
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Solution Overview
Problem
Semiconductor devices face challenges in reducing dynamic switching losses due to the flooding of semiconductor regions with charge carriers, which affects their switching characteristics.
Innovation Solution
The implementation of a power semiconductor device with intersecting first and second trench structures, where the second trench structures extend to a smaller depth than the first, allowing for improved carrier confinement and reduced crosstalk between electrode signals, thereby enhancing switching characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single trench structure is used, then the device structure is simple, but the switching losses are high due to poor carrier confinement
Solution Approach 1:
The single trench structure is divided into multiple intersecting trench structures (first trench structures extending in a first lateral direction and second trench structures extending in a second lateral direction). This segmentation creates a grid-like pattern that improves carrier confinement in both lateral directions, thereby reducing switching losses while maintaining manageable structural complexity
Solution Approach 2:
The invention transitions from a single-direction trench structure to a multi-directional intersecting trench structure system. By adding trenches in a second lateral direction perpendicular to the first lateral direction, the carrier confinement is enhanced in an additional dimension, effectively reducing switching losses without excessive complexity increase
2Reliability
If trench structures extend to great depth, then carrier confinement is improved, but manufacturing complexity increases
Solution Approach 1:
Instead of forming all trench structures to the same maximum depth, the invention uses trenches of different depths (first trench structures at a first depth and second trench structures at a second depth). This partial action approach provides sufficient carrier confinement for device operation while reducing the overall manufacturing complexity and etching requirements compared to forming all trenches to the full depth
3Area of stationary object
If multiple electrodes are placed close together, then device area is reduced, but crosstalk between electrodes increases
Solution Approach 1:
Dielectric material is introduced as an intermediary substance between adjacent electrodes and trench structures. This dielectric layer acts as a mediator that electrically isolates neighboring electrodes, preventing crosstalk while allowing the electrodes to be positioned closely together, thus maintaining compact device area
Data Source
AI summary
A power semiconductor device first trench structures extending from a first main surface into a semiconductor body up to a first depth. The first trench structures extend in parallel along a first lateral direction. Each first trench structure includes a first dielectric and a first electrode. The power semiconductor device further includes second trench structures extending from the first main surface into the semiconductor body up to a second depth that is smaller than the first depth. The second trench structures extend in parallel along a second lateral direction and intersect the first trenches at intersection positions. Each second trench structure includes a second dielectric and a second electrode. The second dielectric is arranged between the first electrode and the second electrode at the intersection positions.