Dummy Gate Overlap on Isolation Regions to Prevent MOSFET Leakage
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Solution Overview
Problem
The scaling down of semiconductor devices, such as MOSFETs, leads to challenges in device packing density and performance due to leakage issues caused by improperly formed epitaxial features adjacent to dummy gates.
Innovation Solution
The configuration of semiconductor devices is adjusted to improve the formation of epitaxial features by ensuring that dummy gates overlap with isolation regions, preventing exposure of the isolation region surfaces during epitaxial growth, and thereby enhancing the uniformity and volume of the epitaxial features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If device geometry is scaled down to increase production efficiency, then productivity is improved, but leakage issues worsen due to improperly formed epitaxial features
Solution Approach 1:
The dummy gate is formed to overlap with the isolation region before epitaxial growth occurs. This preliminary structural configuration prevents the epitaxial material from directly contacting the isolation region surface, thereby preventing leakage paths from forming during subsequent processing steps while allowing continued device scaling for high productivity
2Reliability
If dummy gates are positioned to overlap isolation regions to prevent leakage, then reliability is improved, but device complexity increases due to configuration adjustments
Solution Approach 1:
The dummy gate structure is merged with the isolation region by positioning the dummy gate to overlap the isolation region. This combination creates a unified structure that simultaneously serves as a dummy gate for epitaxial feature formation and provides leakage prevention by blocking direct contact between epitaxial material and the isolation region, thereby improving reliability without proportionally increasing device complexity
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 improves device performance by reducing leakage issues, achieving more uniform electrical properties, and ensuring proper contact between conductive contacts and epitaxial features.
Implementation Method 1
preventing exposure of the isolation region surfaces during epitaxial growth
Data Source
AI summary
The present disclosure provides a semiconductor device, including a substrate, a first active region in the substrate, a second active region in the substrate and adjacent to the first active region, an isolation region in the substrate and between the first active region and the second active region, and a dummy gate overlapping with the isolation region, wherein an entire bottom width of the dummy gate is greater than an entire top width of the isolation region.