FinFET Gate Structure with Segmented Work Functions
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Solution Overview
Problem
Current fin-shaped structure designs in FinFET fabrication suffer from current leakage issues, affecting the overall performance of semiconductor devices.
Innovation Solution
A method involving the formation of fin-shaped structures on a substrate with shallow trench isolation and a gate structure comprising different work function portions, which allows for improved control over the channel region and threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fin-shaped structures are used to increase channel control and reduce short channel effects, then device performance is improved, but current leakage occurs affecting overall device performance
Solution Approach 1:
The gate structure is divided into multiple regions with different work functions: a first gate region with first work function and a second gate region with second work function. This local differentiation allows optimal control over different portions of the channel, suppressing current leakage in specific regions while maintaining high performance in others.
Solution Approach 2:
The gate structure is segmented into distinct portions with different material compositions or doping levels, creating multiple gate regions that can independently control different sections of the fin channel. This segmentation enables targeted suppression of leakage paths while preserving beneficial current flow regions.
2Reliability
If gate structure controls channel region effectively, then drain-induced barrier lowering is reduced, but threshold voltage control becomes complex
Solution Approach 1:
Different gate regions are assigned different work functions to independently control threshold voltage in respective channel portions. The first gate region with first work function controls one section while the second gate region with second work function controls another section, enabling multi-point threshold voltage control.
Solution Approach 2:
The work function parameter is varied across different gate regions through material selection or doping adjustments. By changing the work function parameter locally, the invention achieves independent threshold voltage control in different gate regions, managing complexity through parameter differentiation.
Data Source
AI summary
A method for fabricating semiconductor device includes the steps of: forming a first fin-shaped structure on a substrate; forming a shallow trench isolation (STI) adjacent to the first fin-shaped structure; and forming a gate structure on the first fin-shaped structure and the STI. Preferably, the gate structure comprises a left portion and the right portion and the work functions in the left portion and the right portion are different.