Multi-Sheet Gate Structure for Threshold Voltage Control
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Solution Overview
Problem
Existing semiconductor devices face challenges in scaling integrated circuit density and managing short channel effects while maintaining effective current control, particularly in multi-gate transistors with three-dimensional channels.
Innovation Solution
The semiconductor device incorporates multi-gate transistors with varying sheet patterns and gate electrodes, featuring distinct work function controlling films and filling conductive films to manage spacing and thickness differences between active patterns, enhancing current control and reducing short channel effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-gate transistors with uniform structure are used across the substrate, then manufacturing simplicity is maintained, but threshold voltage control flexibility is limited
Solution Approach 1:
The patent applies local quality by forming work function controlling films with different thicknesses in different regions of the substrate. Specifically, a first work function controlling film is formed in a first region and a second work function controlling film is formed in a second region, where the second work function controlling film has a greater thickness than the first. This enables different threshold voltages to be achieved in different regions without changing the overall transistor structure, thus resolving the contradiction between threshold voltage control flexibility and structure uniformity.
2Reliability
If gate length is increased to improve current control, then current control capability improves, but device area increases
Solution Approach 1:
The patent applies parameter changes by modifying the work function of the gate electrode through controlled variation in the thickness of the work function controlling film. By adjusting the film thickness in different regions, different threshold voltages are achieved, which directly improves current control capability without requiring changes to the gate length or other geometric parameters, thus avoiding an increase in device area.
3Productivity
If multi-gate transistor density is increased to improve integrated circuit density, then productivity improves, but short channel effects become more severe
Solution Approach 1:
The patent applies local quality by implementing region-specific work function controlling films that enable different threshold voltages in different areas of the integrated circuit. This allows high-density multi-gate transistor configurations to be maintained while using locally optimized threshold voltages to suppress short channel effects in specific regions, thus resolving the contradiction between integrated circuit density and short channel effect suppression.
Data Source
AI summary
A semiconductor device includes first and second sheet patterns spaced apart from each other on a first region of the substrate, a first gate electrode extending between the first and second sheet patterns, third and fourth sheet patterns spaced apart from each other on a second region of the substrate, and a second gate electrode extending between the third and fourth sheet patterns. The first gate electrode includes a first work function controlling film, which is between the first and second sheet patterns, and a first filling conductive film on the first work function controlling film. The second gate electrode includes a second work function controlling film, which is between the third and fourth sheet patterns, and a second filling conductive film on the second work function controlling film. A distance between the third and fourth sheet patterns is greater than a distance between the first and second sheet patterns.