Segmented Deep Trench Isolation with Doped Sheath
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving effective electrical isolation between regions with high voltage and low voltage components due to stress issues at trench intersections.
Innovation Solution
A semiconductor device design featuring a trench structure with a doped sheath surrounding first and second trenches, extending from the top surface to an isolation layer, providing electrical isolation between regions with a conductivity type difference, and a trench space configuration that reduces stress levels compared to traditional intersection designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional trench intersection designs are used to achieve electrical isolation, then isolation effectiveness is improved, but stress levels in semiconductor regions increase
Solution Approach 1:
The continuous trench structure is segmented into multiple discrete trenches separated by trench spaces. This segmentation allows the trenches to be positioned at optimized locations rather than forming a continuous barrier, reducing stress concentration while maintaining electrical isolation effectiveness through strategic placement of isolated regions between trenches.
Solution Approach 2:
Trench spaces act as intermediary regions between adjacent trenches. These spaces provide physical separation that reduces stress interaction between trenches while the doped sheaths in the trenches maintain electrical isolation. The intermediary spaces allow stress to be distributed more evenly across the semiconductor layer.
2Reliability
If trench width is increased to improve isolation, then electrical isolation is enhanced, but device area increases
Solution Approach 1:
Instead of using a single wide trench, the isolation structure is segmented into multiple narrower trenches separated by trench spaces. This segmentation achieves equivalent or superior electrical isolation through cumulative effect of multiple trenches while the trench spaces reduce the total area occupied compared to a continuous wide trench.
Solution Approach 2:
The isolation approach transitions from relying solely on trench width (one dimension) to utilizing both trench width and trench spacing (adding spatial distribution as another dimension). This dimensional change allows optimization of isolation effectiveness while controlling overall area through strategic arrangement of segmented trenches.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves a desired level of electrical isolation with reduced stress in the semiconductor regions, enhancing the performance and reliability of semiconductor devices.
Implementation Method 1
The doped sheath has a first conductivity type and extends from the top surface to the isolation layer and from the first trench to the second trench across the trench space
Data Source
AI summary
A semiconductor device has a first trench and a second trench of a trench structure located in a substrate. The second trench is separated from the first trench by a trench space that is less than a first trench width of the first trench and less than a second trench width of the second trench. The trench structure includes a doped sheath having a first conductivity type, contacting and laterally surrounding the first trench and the second trench. The doped sheath extends from the top surface to an isolation layer and from the first trench to the second trench across the trench space. The semiconductor device includes a first region and a second region, both located in the semiconductor layer, having a second, opposite, conductivity type. The first region and the second region are separated by the first trench, the second trench, and the doped sheath.