3D FinFET Structure With Step-Like Fin Geometry for Density Scaling
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Solution Overview
Problem
Current FinFET technologies face challenges in scaling down transistor density due to difficulties in controlling Fin Body width and shape, leading to increased pitch and reduced transistor density, which fails to meet Moore's Law demands for more transistors per unit area and higher cost efficiency.
Innovation Solution
A new Fin structure transistor with precise and well-controlled geometries is developed, featuring a semiconductor substrate with a fin structure that includes a fin body and base, where the fin structure has a step-like transition and is surrounded by a shallow trench isolation region, allowing for independent conductive structures that reduce the planar area and prevent Fin structure collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pitch of the Fin Body is scaled down to increase transistor density, then the number of transistors per unit area increases, but the Fin Body width becomes difficult to control precisely and the Fin structure becomes unstable
Solution Approach 1:
The Fin Body is divided into two distinct regions: a first Fin Body region with a first width under the gate structure, and a second Fin Body region with a second width under the source/drain structures. This segmentation allows each region to be independently controlled and optimized, enabling precise width control even as overall pitch is scaled down to increase transistor density.
Solution Approach 2:
Different regions of the Fin Body are given different local properties: the first Fin Body region under the gate has a specific width optimized for gate control, while the second Fin Body region under source/drain has a different width optimized for contact and doping. This local differentiation maintains manufacturing precision across the entire structure despite overall scaling.
2Quantity of substance
If the Fin Body width is reduced to increase transistor density, then more transistors fit per unit area, but the Fin structure becomes prone to collapse and bending
Solution Approach 1:
By segmenting the Fin Body into regions with different widths, the structure gains localized reinforcement. The second Fin Body region under source/drain structures can be widened to provide structural support and prevent collapse, while the first region under the gate maintains narrow dimensions for high density, thus reliability is preserved during scaling.
Solution Approach 2:
The Fin Body exhibits local quality variations where different segments have different widths tailored to their functional requirements. This local differentiation ensures that critical regions for structural integrity maintain sufficient width to prevent bending and collapse, even as overall transistor density increases through scaling.
3Productivity
If the Fin Body shape is made sharper to improve device performance, then transistor performance increases, but the shape becomes difficult to maintain consistency and variations increase
Solution Approach 1:
The Fin Body shape is segmented into different regional profiles: the first region under the gate can have a sharper profile for optimized electric field distribution and performance, while the second region under source/drain can have a different profile for structural stability. This segmentation allows performance optimization without sacrificing shape consistency across the entire structure.
Solution Approach 2:
Different local regions of the Fin Body are given different shape characteristics optimized for their specific functions. The gate region can have sharper features for performance while source/drain regions have more robust features for manufacturing consistency, resolving the contradiction between performance and shape uniformity.
4Manufacturing precision
If the pitch is increased to maintain Fin Body control, then manufacturing precision improves, but the planar area occupied by each transistor increases
Solution Approach 1:
By segmenting the Fin Body into regions with different widths, the patent achieves precise control of critical dimensions in the gate region without requiring increased overall pitch. The segmented structure allows narrow gate regions for high density while providing wider support regions for manufacturing precision, thus reducing total transistor area while maintaining control.
Solution Approach 2:
The local differentiation of Fin Body widths allows each region to be optimized independently: the gate region achieves the precision needed for manufacturing control while the source/drain regions provide structural support. This eliminates the need to increase overall pitch, thereby minimizing transistor planar area.
Data Source
AI summary
The present invention provides a fin structure transistor with precise and well-controlled geometries. Such fin structure transistor comprises a semiconductor substrate with an original surface and an active region formed based on the semiconductor substrate, the active region has a fin structure. A shallow trench isolation region surrounds the active region and a gate structure of the transistor crosses over the fin structure and covers a first portion of the shallow trench isolation region. Wherein the fin structure includes a fin body covered by the gate structure and a fin base portion of which is not covered by the gate structure, and a step-like transition is between the fin body and the fin base.