Cut Metal Gate Refill With Air Gap for FinFET Leakage Isolation
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Solution Overview
Problem
As the minimum feature sizes in semiconductor devices decrease, leakage current between cut replacement gates in FinFETs becomes more problematic due to the decreased spacing between the cut ends of the gate.
Innovation Solution
The implementation of a gate cutting technique that forms a dielectric material with an air gap or void between the cut ends of adjacent FinFET gates, enhancing insulating capabilities and reducing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are reduced to increase integration density, then more components can be integrated into a given area, but leakage current between adjacent gates increases
Solution Approach 1:
The gate structure is segmented into multiple sections with dielectric material regions inserted between adjacent gates. This segmentation creates electrical isolation between neighboring gates, preventing leakage current while maintaining high integration density through compact layout of the segmented gate structures.
Solution Approach 2:
A dielectric material is introduced as an intermediary substance between adjacent metal gates. This dielectric layer acts as an electrical insulator that blocks leakage current paths between gates, enabling closer spacing of gates without compromising electrical isolation.
2Area of stationary object
If spacing between cut gate ends is reduced, then integration density increases, but leakage current between adjacent gates worsens
Solution Approach 1:
A dielectric material is introduced as an intermediary substance between adjacent metal gates. This dielectric layer acts as an electrical insulator that blocks leakage current paths between gates, enabling closer spacing of gates without compromising electrical isolation.
Solution Approach 2:
The gate structure employs composite material construction with metal gates combined with dielectric material regions. This composite approach allows the conductive metal portions to be closely spaced for high density while the dielectric portions provide electrical isolation to prevent leakage current.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The air gap provides improved insulation, effectively reducing leakage current between adjacent FinFET gates, thereby addressing the challenge of increased leakage as feature sizes diminish.
Implementation Method 1
The air gap provides enhanced insulating capabilities over the dielectric material and as a result the leakage current from one gate to the other gate is reduced
Data Source
AI summary
A gate stack can be etched to form a trench extending through the gate stack, the trench removing a portion of the gate stack to separate the gate stack into a first gate stack portion and a second gate stack portion. A dielectric material is deposited in the trench to form a dielectric region, the dielectric region having an air gap in the dielectric material. The air gap may extend upward from beneath the gate stack to an area interposed between the end of the first gate stack portion and the end of the second gate stack portion. Contacts to the first gate stack portion and contacts to the second gate stack portion may be formed which are electrically isolated from each other by the dielectric material and air gap formed therein.