Bottom Isolation Structure for Multi-Gate Leakage Control
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Solution Overview
Problem
The integration of multi-gate devices in semiconductor manufacturing is challenging due to complexity and the need for improved gate control and reduced short-channel effects, which are not adequately addressed by existing fabrication processes.
Innovation Solution
A semiconductor structure with nanostructures and source/drain structures is developed, incorporating a bottom isolation feature under the channel region and source/drain structures, using a combination of photolithography and self-aligned processes to pattern nanostructures, and forming isolation features to prevent leakage and enhance device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-gate devices are integrated to improve gate control and reduce short-channel effects, then device performance is improved, but fabrication process complexity increases
Solution Approach 1:
The fabrication process is divided into distinct stages: forming sacrificial structures, depositing semiconductor layers, patterning gate regions, and removing sacrificial materials. This segmentation allows complex multi-gate devices to be constructed through manageable sequential steps, reducing overall process complexity while maintaining improved gate control.
Solution Approach 2:
Sacrificial structures are formed in advance before the actual multi-gate device fabrication. These preliminary structures guide subsequent processing steps and enable precise positioning of gate electrodes, thereby simplifying the overall fabrication process while ensuring accurate gate control.
2Productivity
If device dimensions are scaled down to improve production efficiency and lower costs, then productivity increases, but manufacturing precision requirements increase
Solution Approach 1:
Self-aligned processes are employed where previously deposited structures automatically serve as alignment references for subsequent patterning steps. This self-service mechanism eliminates the need for separate alignment operations, maintaining high manufacturing precision even as feature sizes are scaled down to improve productivity.
Solution Approach 2:
The patent utilizes changes in material properties and deposition parameters to achieve precise patterning at reduced dimensions. By adjusting deposition conditions and material selection, high precision is maintained despite smaller minimum feature sizes required for improved production efficiency.
3Reliability
If isolation features are added to prevent leakage and enhance device performance, then reliability improves, but device complexity increases
Solution Approach 1:
Isolation features are merged with the gate electrode structures and sacrificial material removal processes. The same processing steps that define the gate regions also create the isolation features, thereby preventing leakage and enhancing device reliability without significantly increasing structural or process complexity.
Solution Approach 2:
Sacrificial structures serve as intermediary elements that simultaneously define gate regions and create isolation features. These intermediary structures enable dual functionality during fabrication, improving reliability through leakage prevention while avoiding additional complexity by using existing process elements.
Data Source
AI summary
Semiconductor structures and methods for manufacturing the same are provided. The semiconductor structure includes a substrate and a bottom isolation feature formed over the substrate. The semiconductor structure also includes a bottom semiconductor layer formed over the bottom isolation feature and nanostructures formed over the bottom semiconductor layer. The semiconductor structure also includes a source/drain structure attached to the nanostructures and covering a portion of the bottom isolation feature.