FinFET Device Isolation Layer Segmentation and Liner Design
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving improved device isolation characteristics and preventing electrical shorts, which affect the operating characteristics and scalability of multi-gate transistors.
Innovation Solution
A semiconductor device design featuring a fin protruded from a substrate with intersecting gate structures, a recess filled with a device isolation layer, and a liner along the sidewalls, where the device isolation layers have different widths and materials, and a spacer interposed between the source/drain region and the device isolation layer, enhancing isolation and preventing electrical shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a device isolation layer is formed to improve device isolation characteristics, then electrical short prevention is improved, but the complexity of the device structure increases
Solution Approach 1:
The device isolation layer is divided into multiple segments including a first device isolation layer, a second device isolation layer, and a third device isolation layer with different widths. This segmentation allows each layer to serve specific isolation functions while maintaining overall structural organization and preventing electrical shorts between adjacent devices.
Solution Approach 2:
Different portions of the device isolation structure have different widths and materials tailored to local requirements. The first device isolation layer has a narrower width than the second device isolation layer, and the third device isolation layer has a yet narrower width. This local variation optimizes isolation effectiveness in different regions while managing overall device complexity.
2Reliability
If the device isolation layer width is increased to improve isolation effectiveness, then electrical short prevention is improved, but the area occupied by the device increases
Solution Approach 1:
The isolation structure is segmented into multiple layers with progressively narrower widths from bottom to top. The first device isolation layer has the narrowest width, the second has a moderate width, and the third has the widest width. This segmentation provides effective isolation at each level while minimizing the total area occupied by the isolation structure.
Solution Approach 2:
Instead of increasing isolation width in a single dimension, the patent uses a multi-dimensional approach with stacked isolation layers of varying widths. This vertical stacking with horizontal variation provides comprehensive isolation coverage while efficiently utilizing the available device area.
3Reliability
If different materials are used for device isolation layers to enhance isolation characteristics, then electrical short prevention is improved, but the manufacturing process complexity increases
Solution Approach 1:
Different materials are assigned to different device isolation layers based on local functional requirements. The first device isolation layer uses a first material, the second device isolation layer uses a second material, and the third device isolation layer uses a third material. This local material optimization enhances isolation characteristics while maintaining a systematic manufacturing approach.
Solution Approach 2:
The device isolation structure employs composite materials with different properties in each layer. This composite approach allows each material to be optimized for its specific isolation function, providing superior overall isolation characteristics while following established multi-layer fabrication processes.
4Reliability
If a liner is added along the sidewalls of the device isolation layer to prevent electrical short, then reliability is improved, but the device complexity increases
Solution Approach 1:
A liner is introduced as an intermediary element along the sidewalls of the device isolation layers. This liner acts as a mediator that provides additional electrical isolation and prevents shorts between adjacent devices while maintaining a clear distinction between the isolation structure and active device regions.
Solution Approach 2:
The liner is implemented as a thin film structure that conforms to the sidewalls of the device isolation layers. This thin film approach provides effective electrical isolation and mechanical protection without significantly increasing the overall device complexity or occupying excessive space.
Data Source
AI summary
A semiconductor device includes a fin protruding from a substrate and extending in a first direction, first and second gate structures intersecting the fin, a recess formed in the fin between the first and second gate structures, a device isolation layer which fills the recess, and which has an upper surface protruded outwardly from the fin and disposed to be coplanar with upper surfaces of the first and second gate structures, a liner formed along a side walls of the device isolation layer protruded outwardly from the fin and a source/drain region disposed at both sides of the recess and spaced apart from the device isolation layer.