Vertical ILD Isolation Structure for Merged Source/Drain Separation
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Solution Overview
Problem
As semiconductor devices continue to shrink, the epitaxially grown source/drain features between adjacent transistors tend to merge, leading to electrical shorting, which can degrade device performance and reduce yield due to the increasing complexity and shrinking spacing between transistors.
Innovation Solution
The formation of isolation structures between the source/drain components, achieved through a process involving sacrificial layers, etching, and dielectric material deposition, to physically and electrically separate the source/drain components and prevent merging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If device geometry is scaled down to increase functional density, then productivity and production efficiency are improved, but the spacing between adjacent transistors decreases causing epitaxial source/drain features to merge and electrical shorting occurs
Solution Approach 1:
The patent introduces isolation structures that segment the continuous epitaxial source/drain regions into separate, electrically isolated components. By dividing the source/drain features with isolation barriers, the patent prevents unintended merging while maintaining scaled-down device dimensions, thus resolving the contradiction between increased functional density and electrical shorting prevention
Solution Approach 2:
The patent employs isolation structures as intermediary elements positioned between adjacent epitaxial source/drain features. These intermediary isolation structures act as barriers that prevent direct electrical contact between merged source/drain regions, enabling continued device scaling while maintaining electrical isolation and preventing shorting
2Area of stationary object
If spacing between adjacent transistors is reduced to increase functional density, then area utilization is improved, but manufacturing precision requirements increase to prevent source/drain merging
Solution Approach 1:
The patent implements isolation structures before the epitaxial growth process, establishing predefined boundaries that guide and constrain the growth of source/drain features. This preliminary action ensures that even with reduced spacing, the epitaxial growth remains controlled and separated, reducing the precision requirements during subsequent manufacturing steps
Solution Approach 2:
The patent applies isolation structures selectively in regions where source/drain merging is most likely to occur, creating localized zones of enhanced separation. This local quality approach allows for reduced overall spacing while maintaining precise separation where critical, thereby improving area utilization without compromising manufacturing precision
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 solution effectively prevents electrical shorting between transistors, enhancing device reliability and performance by maintaining the separation of source/drain components, even as device sizes shrink, thereby improving yield and reliability.
Implementation Method 1
epitaxially grown source/drain components
Implementation Method 2
A material layer, such as an interlayer dielectric (ILD), is formed over the source/drain components
Data Source
AI summary
A semiconductor device includes a first active region and a second active region disposed over a substrate. A first source/drain component is grown on the first active region. A second source/drain component is grown on the second active region. An interlayer dielectric (ILD) is disposed around the first source/drain component and the second source/drain component. An isolation structure extends vertically through the ILD. The isolation structure separates the first source/drain component from the second source/drain component.