Work Function Patterns for Leakage Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices face reliability issues due to high integration, which can lead to increased leakage current and reduced accuracy in electrical conductivity.
Innovation Solution
A semiconductor device design incorporating a substrate with a word line structure that includes a gate insulation pattern, a first work function pattern with a higher work function than the gate electrode pattern, and a second work function pattern, which helps in reducing leakage current and enhancing reliability by adjusting the threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high integration is implemented in semiconductor devices, then device functionality and capacity are improved, but leakage current increases and reliability deteriorates
Solution Approach 1:
The patent applies local quality by implementing work function patterns with different work functions at specific locations within the gate structure. The first work function pattern (e.g., tungsten nitride with work function of 4.5-5.5 eV) is positioned at the interface with the semiconductor substrate, while the second work function pattern (e.g., titanium nitride with work function of 3.5-4.5 eV) is positioned above it. This spatial differentiation of material properties allows localized control of electrical characteristics to reduce leakage current while maintaining overall device functionality.
Solution Approach 2:
The patent changes the work function parameter of the gate structure by introducing multiple layers with different work function values. By adjusting the work function gradient from the substrate interface upward, the threshold voltage is controlled and leakage current is reduced. This parameter modification approach allows the device to maintain high integration benefits while improving reliability through electrical characteristic optimization.
2Productivity
If high integration is implemented in semiconductor devices, then device capacity is improved, but accuracy of electrical conductivity deteriorates
Solution Approach 1:
The work function patterns create local quality variations in the gate structure that precisely control the electrical conductivity characteristics at the semiconductor-gate interface. This localized material property differentiation enables accurate control of threshold voltage and channel conductivity, improving the precision of electrical conductivity while maintaining high device capacity through continued integration.
3Reliability
If work function patterns are added to the gate structure, then leakage current is reduced and reliability is improved, but device complexity increases
Solution Approach 1:
The gate structure is segmented into multiple functional layers: gate insulation pattern, first work function pattern, and second work function pattern. Each layer performs a specific function - the gate insulation provides electrical isolation, the first work function pattern controls the interface properties with the semiconductor substrate, and the second work function pattern adjusts the overall gate characteristics. This segmentation allows reliable leakage current reduction while keeping the added complexity manageable through clear functional division.
Solution Approach 2:
The work function patterns serve multiple functions simultaneously: they control threshold voltage, reduce leakage current, and provide interface engineering between different materials. This multi-functionality reduces the need for separate structures, thereby limiting the increase in device complexity while achieving improved reliability.
Data Source
AI summary
A semiconductor device includes a substrate including an active region defined by a device isolation layer. A word line structure is in a trench formed in an upper portion of the substrate. The word line structure includes a gate insulation pattern covering an inner surface of the trench. A gate electrode pattern is on the gate insulation pattern. A first work function pattern is between the gate insulation pattern and the gate electrode pattern. A second work function pattern is on the first work function pattern and extends along a side surface of the gate electrode pattern. The first work function pattern has a top surface at a level below that of a bottom surface of the gate electrode pattern. The first work function pattern has a work function greater than that of the second work function pattern.