Insulating Fin Structure for Source/Drain Separation in Nanosheet Devices
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Solution Overview
Problem
As the minimum feature sizes in semiconductor devices are reduced, issues such as undesired merging of source/drain regions and extrusion defects due to local grain growth on insulating fin surfaces become significant challenges.
Innovation Solution
The use of insulating fins with alternating high-k dielectric layers and capping layers between stacks of nanostructures helps reduce the merging of source/drain regions and improves film quality, while the capping layers specifically address extrusion defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If minimum feature sizes are reduced to increase integration density, then more components can be integrated into a given area, but undesired merging of source/drain regions occurs
Solution Approach 1:
An insulating fin structure is introduced as an intermediary element positioned between adjacent source/drain regions. This insulating fin acts as a physical barrier that prevents the merging of source/drain regions while allowing the minimum feature size to be reduced for higher integration density. The insulating fin is formed from dielectric material and is integrated into the semiconductor structure without requiring additional complex processing steps.
Solution Approach 2:
The solution addresses the two-dimensional planar merging problem by introducing a vertical dimension element - the insulating fin extends vertically from the substrate surface. This vertical structure provides separation in the vertical dimension while allowing horizontal integration density to increase, effectively using dimensional transition to resolve the contradiction between miniaturization and region separation.
2Productivity
If minimum feature sizes are reduced to increase integration density, then more components can be integrated into a given area, but extrusion defects due to local grain growth on insulating fin surfaces occur
Solution Approach 1:
The material composition of the insulating fin is modified by forming alternating layers of high-k dielectric material and capping material. This compositional parameter change suppresses local grain growth on the insulating fin surface, preventing extrusion defects while maintaining the structural integrity needed for high integration density applications.
Solution Approach 2:
The insulating fin is constructed as a composite structure with alternating layers of high-k dielectric material and capping material. This composite material approach combines the benefits of high-k dielectric for electrical isolation with the capping material's ability to suppress grain growth, thereby eliminating extrusion defects while maintaining film quality for high-density integration.
3Manufacturing precision
If insulating fins are used to prevent merging of source/drain regions, then source/drain region separation is improved, but device complexity increases
Solution Approach 1:
The insulating fin is segmented into alternating layers of high-k dielectric material and capping material. This segmentation serves multiple functions: it provides source/drain region separation while suppressing grain growth through the capping layers. The segmented structure achieves complex functionality through modular layering rather than requiring a single complex component.
Data Source
AI summary
A semiconductor device includes a first channel region, a second channel region, and a first insulating fin, the first insulating fin being interposed between the first channel region and the second channel region. The first insulating fin includes a lower portion and an upper portion. The lower portion includes a fill material. The upper portion includes a first dielectric layer on the lower portion, the first dielectric layer being a first dielectric material, a first capping layer on the first dielectric layer, the first capping layer being a second dielectric material, the second dielectric material being different than the first dielectric material, and a second dielectric layer on the first capping layer, the second dielectric layer being the first dielectric material.