Semiconductor Isolation Structure for Stress-Controlled Multi-Gate Transistors
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving improved integration, reliability, and performance, particularly in scaling techniques for multi-gate transistors, where the short channel effect and stress distribution across different active patterns complicate the fabrication process and affect device performance.
Innovation Solution
The semiconductor device incorporates a field insulating film and an element isolation structure with specific material choices and stress applications, where the element isolation structure extends across active patterns and field insulating films, applying compressive or tensile stress to manage stress distribution and improve performance, while maintaining a complex but controlled fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-gate transistors are used for scaling, then current control capability is improved, but short channel effect becomes more severe
Solution Approach 1:
The patent transitions from planar 2D channels to three-dimensional 3D channels using multi-gate transistor structures (FinFET, nanowire, nanosheet). This dimensional change provides better gate control over the channel from multiple directions, improving current control capability while the specific geometric configurations help mitigate short channel effects through enhanced electrostatic control.
Solution Approach 2:
The patent applies different stress conditions (tensile stress for NMOS, compressive stress for PMOS) to specific active patterns in different regions. By locally optimizing the stress state in n-type and p-type semiconductor regions, the device achieves improved carrier mobility and performance while managing short channel effects in a region-specific manner.
2Reliability
If element isolation structures are formed in isolation trenches, then device isolation is improved, but fabrication process complexity increases
Solution Approach 1:
The patent divides the semiconductor structure into distinct regions separated by element isolation structures formed in isolation trenches. These trenches segment the substrate into isolated active patterns, providing electrical isolation between devices. The segmentation approach enables independent fabrication and optimization of different device regions while maintaining overall system functionality.
Solution Approach 2:
The element isolation structures act as intermediary elements between active patterns and other device components. These isolation structures provide a mediating function by electrically separating adjacent devices while allowing the fabrication process to proceed systematically through defined stages, managing complexity through structured intermediate steps.
3Reliability
If stress is applied to active patterns, then carrier mobility is improved, but stress distribution control becomes more difficult
Solution Approach 1:
The patent implements different stress conditions in different regions: tensile stress is applied to n-type semiconductor active patterns while compressive stress is applied to p-type semiconductor active patterns. This local quality approach optimizes carrier mobility for each device type by matching the stress type to the carrier type (electrons for NMOS, holes for PMOS), while the selective application method enables precise control over stress distribution across the device array.
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 configuration enhances the integration, reliability, and performance of semiconductor devices by effectively managing stress and reducing the short channel effect, thereby improving the overall performance of both NMOS and PMOS regions without compromising the complexity of the fabrication process.
Implementation Method 1
applying compressive or tensile stress to manage stress distribution and improve performance
Data Source
AI summary
A semiconductor device includes a first active pattern extending lengthwise along a first direction and a second active pattern extending lengthwise along the first direction and spaced apart from the first active pattern in the first direction. The device also includes a field insulating film between the first active pattern and the second active pattern. An upper surface of the field insulating film is lower than or coplanar with upper surfaces of the first and second active patterns. The device further includes an element isolation structure in an isolation trench in the first active pattern and the field insulating film. An upper surface of the element isolation structure is higher than the upper surfaces of the first and second active patterns.