Dual-Layer Isolation Structure for Semiconductor Active Regions
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Solution Overview
Problem
As semiconductor devices achieve higher integration levels, the electrical insulative characteristics between neighboring active regions deteriorate, leading to issues with isolation and transistor performance.
Innovation Solution
A semiconductor device design featuring a dual-layer isolation structure with a wider lower isolation pattern under a narrower upper pattern, where the upper pattern serves as a mask for ion implantation, preventing impurity diffusion and enhancing isolation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer isolation structure is used, then the device structure remains simple, but the electrical insulative characteristics between neighboring active regions deteriorate due to high integration degree
Solution Approach 1:
The isolation structure is divided into two distinct layers: a first isolation pattern at a first depth and a second isolation pattern at a second depth. This segmentation allows each layer to contribute to electrical isolation independently, with the wider lower pattern providing a broader isolation base and the upper pattern providing additional isolation coverage, thereby improving overall electrical insulative characteristics between neighboring active regions
Solution Approach 2:
The patent introduces a vertical dimensionality change by positioning the first isolation pattern at a first depth and the second isolation pattern at a second depth different from the first depth. This multi-level vertical arrangement creates three-dimensional isolation that effectively blocks electrical leakage paths that would exist in conventional single-layer isolation structures, significantly enhancing electrical insulation reliability
2Reliability
If the isolation pattern width is increased to improve isolation, then electrical insulation improves, but the transistor threshold voltage changes more significantly
Solution Approach 1:
The patent applies local quality by making the first isolation pattern have a first width and the second isolation pattern have a second width that is different from the first width. Specifically, the lower isolation pattern is designed with a larger width to provide strong isolation at the critical interface region, while the upper isolation pattern has a smaller width. This differentiated width design allows effective isolation without excessively broadening the isolation region at all levels, thereby minimizing impact on transistor threshold voltage while maintaining isolation effectiveness
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
This design effectively improves isolation between active regions, reducing changes in transistor threshold voltages and maintaining electrical integrity.
Implementation Method 1
an ion implantation process may be performed to empower the isolation characteristics. Additionally, the isolation pattern may be formed on the sidewall of the trench, and may serve as a portion of the ion implantation mask
Data Source
AI summary
A semiconductor device includes a first isolation structure extending through an upper portion of a substrate and defining a first active region, a first gate structure on the substrate, and first source/drain regions at upper portions of the first active region adjacent to the first gate structure. The first isolation structure includes an upper isolation pattern structure and a lower isolation pattern. The upper isolation pattern structure includes a first isolation pattern and a second isolation pattern covering a sidewall of the first isolation pattern. The lower isolation pattern is formed under and contacting the upper isolation pattern structure, and a width of the lower isolation pattern is greater than a width of the upper isolation pattern structure.