Forksheet Wall Isolation Using Dual Liners for Fin Protection
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Solution Overview
Problem
Nanosheet devices face issues with interference and defects during scaling due to insufficient isolation of components, leading to performance degradation.
Innovation Solution
A dual-layer liner structure comprising a first liner of SiO2 and a second liner of SiN is applied to isolate fins, preventing oxidation and charge defects during the formation of shallow trench isolation layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nanosheet devices are scaled down and components are placed closer together, then device density and integration are improved, but interference between components increases and defects form during processing
Solution Approach 1:
A dual-layer liner structure comprising a first liner (215) and a second liner (230) is introduced as an intermediary between adjacent fins (205). The first liner provides initial isolation, while the second liner extends over the top surface of the first liner to provide additional isolation. This intermediary structure prevents direct electrical interaction between fins and prevents oxidation during shallow trench isolation formation, thereby maintaining component isolation at high device densities.
2Reliability
If isolation structures are added to prevent interference, then component isolation is improved, but device complexity increases
Solution Approach 1:
The isolation structure is segmented into two distinct layers: a first liner (215) that provides baseline isolation and a second liner (230) that provides enhanced protection. The first liner can be formed using standard deposition processes, while the second liner is selectively formed to extend over the first liner's top surface. This segmentation allows each layer to be optimized for its specific function, preventing oxidation and electrical interference without requiring a completely complex isolation system.
Solution Approach 2:
The second liner (230) is applied locally only where needed - specifically extending over the top surface of the first liner (215) at fin regions requiring enhanced protection during shallow trench isolation formation. This localized application provides targeted isolation where interference and oxidation risks are highest, while avoiding unnecessary complexity in regions where the first liner suffices.
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 dual-layer liner effectively isolates nanosheet components, preventing oxidation and charge defects, thereby enhancing device performance and reliability.
Implementation Method 1
The first liner isolates the first and second fin from electrically interacting with the second liner
Implementation Method 2
preventing oxidation and charge defects during the formation of shallow trench isolation layers
Implementation Method 3
A shallow trench isolation layer located adjacent to the second liner
Data Source
AI summary
A microelectronic structure that includes a forksheet device that includes a first fin and a second fin and plurality of channel layers located above the first and second fin. A first liner located along each sidewall of the fin and a second liner located along the surface of the first liner. The first liner isolates the fin from electrically interacting with the second liner. A shallow trench isolation layer located adjacent to the second liner.