MOSFET Gate Isolation Layout for Leakage and Short-Channel Control
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Solution Overview
Problem
As semiconductor devices are scaled down, they become susceptible to short channel effects and tunneling effects, impacting their operating characteristics, and existing methods struggle to maintain performance and integration while addressing these challenges.
Innovation Solution
The semiconductor device incorporates a substrate with active regions, device isolation layers, gate electrodes, and insulating patterns, including a concave top surface device isolation layer and gate cutting patterns, to enhance electrical characteristics and reliability by preventing capacitor/gate leakage and adjusting the depth of gate structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MOSFET sizes are scaled down to increase integration density, then device integration is improved, but short channel effects and tunneling effects worsen, impacting operating characteristics
Solution Approach 1:
The patent applies local quality by forming a gate insulating layer with different material compositions in different regions: a first gate insulating layer with higher dielectric constant in the channel region and a second gate insulating layer with lower dielectric constant in the source/drain regions. This spatial variation in material properties allows the device to maintain strong gate control in the channel while reducing tunneling effects at the source/drain interfaces, thus resolving the contradiction between scaling and reliability.
2Length of moving object
If device sizes are reduced, then integration is improved, but susceptibility to short channel effects and tunneling effects increases
Solution Approach 1:
The patent implements local quality by creating a non-uniform gate insulating layer structure where the dielectric constant varies spatially. The first gate insulating layer with higher dielectric constant is positioned in the channel region to enhance gate control, while the second gate insulating layer with lower dielectric constant is positioned in the source/drain regions to suppress tunneling effects. This localized differentiation allows small devices to maintain reliability despite reduced dimensions.
3Manufacturing precision
If gate insulating layer is made thinner to improve gate control, then electrical characteristics are improved, but leakage current increases
Solution Approach 1:
The patent applies parameter changes by varying the dielectric constant parameter of the gate insulating layer across different device regions. Instead of uniformly thinning the gate insulating layer, the invention uses a composite structure with regions of different dielectric constants, allowing thin effective gate control in the channel while maintaining higher physical thickness in source/drain regions to prevent leakage, thus resolving the contradiction between gate control and leakage current.
Data Source
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AI summary
A semiconductor device includes a substrate including first and second active regions (NR, PR), a first active pattern (AP1) on the first active region, a second active pattern (AP2) on the second active region, a device isolation layer (ST) filling a trench (TR) between the first active pattern and the second active pattern, the device isolation layer having a concave top surface, a first gate electrode (GE) in the first active region, a second gate electrode (GE) in the second active region, a gate cutting pattern (CT) disposed between the first gate electrode and the second gate electrode and separating the first gate electrode and the second gate electrode, and an insulating pattern (IP) between the gate cutting pattern and the concave top surface of the device isolation layer.