Dummy Gate Structure With Thick Dielectric Layer
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Solution Overview
Problem
Conventional semiconductor fabrication techniques fail to adequately address leakage current issues through dummy gates in multi-gate devices like FinFETs, particularly due to the use of thin dielectric layers that do not provide sufficient electrical isolation, leading to performance and reliability challenges.
Innovation Solution
Implementing a thicker dielectric layer, similar to that used in I/O transistors, specifically for critical dummy gates to enhance electrical isolation and ensure the dummy gates remain electrically non-functional during device operation, while using a thin dielectric layer for other dummy and active gates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thin dielectric layer is used for dummy gates, then manufacturing complexity is reduced and processing is simplified, but leakage current increases and electrical isolation is insufficient
Solution Approach 1:
The patent applies different dielectric layer thicknesses to different gate structures: thin dielectric layers for active gates and thick dielectric layers for dummy gates. This local differentiation allows active gates to maintain proper electrical isolation while dummy gates achieve sufficient electrical isolation to prevent leakage current, resolving the contradiction between manufacturing simplicity and reliability.
2Reliability
If a thick dielectric layer is used for all dummy gates, then leakage current is reduced and electrical isolation is enhanced, but manufacturing complexity increases and processing becomes more difficult
Solution Approach 1:
The patent implements selective thick dielectric layer formation only for dummy gates that require enhanced electrical isolation, while using thin dielectric layers for active gates. This localized approach enhances reliability where needed without unnecessarily complicating the overall manufacturing process, as the thick dielectric formation is targeted specifically to dummy gate regions.
Solution Approach 2:
The patent segments the dielectric layer formation process into distinct stages: initial thin dielectric layer formation for all gates, followed by selective thick dielectric layer formation for dummy gates. This segmentation allows the manufacturing process to maintain simplicity for the majority of structures while adding enhanced isolation only where required by reliability demands.
3Manufacturing precision
If dummy gates are used to provide uniform processing environment, then manufacturing consistency is improved, but leakage current through dummy gates degrades device performance
Solution Approach 1:
The patent maintains the uniform processing environment provided by dummy gates while locally enhancing the dielectric layer thickness for dummy gates to suppress leakage current. This selective thickening preserves the manufacturing precision benefits of dummy gates (uniform etching, deposition, and planarization) while eliminating their harmful leakage effect through targeted electrical isolation enhancement.
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
This approach significantly reduces leakage current through critical dummy gates, improving the performance and reliability of multi-gate devices by providing enhanced electrical isolation without affecting the functionality of active gates.
Implementation Method 1
a critical dummy gate including a thick dielectric layer... providing enhanced electrical isolation
Data Source
AI summary
A structure and method for implementation of dummy gate structures within multi-gate device structures includes a semiconductor device including an isolation region that separates a first and second active region. The first active region is adjacent to a first side of the isolation region and the second active region is adjacent to a second side of the isolation region. A device including a source, a drain, and a gate is formed within the first active region. One of the source and drain regions are disposed adjacent to the isolation region. A dummy gate is formed at least partially over the isolation region and adjacent to the one of the source and drain regions. In various examples, the gate includes a first dielectric layer having a first thickness and the dummy gate includes a second dielectric layer having a second thickness greater than the first thickness.