Source/Drain Recess Dielectric Treatment for Leakage Isolation
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Solution Overview
Problem
As semiconductor devices continue to reduce minimum feature sizes for increased integration density, issues such as leakage between source/drain regions and underlying substrates, and parasitic capacitance between gate electrodes and source/drain regions become significant challenges.
Innovation Solution
A treatment process is applied to the dielectric layer underlying the source/drain regions to enhance its resistance to etching and cleaning processes, reducing leakage and parasitic capacitance by densifying the dielectric layer and eliminating dangling bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the minimum feature size is reduced to increase integration density, then more components can be integrated into a given area, but leakage between source/drain regions and underlying substrates increases
Solution Approach 1:
The patent applies different dielectric materials with different properties at different locations: a first dielectric material is used in the source/drain region where leakage prevention is critical, while a second dielectric material is used in other regions. This local differentiation allows targeted leakage reduction without compromising overall device performance.
Solution Approach 2:
The patent employs a composite dielectric structure combining two different dielectric materials. The first dielectric material (e.g., silicon nitride or silicon oxynitride) is specifically positioned under source/drain regions to provide leakage blocking, while the second dielectric material serves as the bulk dielectric, creating a composite structure that addresses both leakage and capacitance issues.
2Productivity
If the minimum feature size is reduced to increase integration density, then more components can be integrated into a given area, but parasitic capacitance between gate electrodes and source/drain regions increases
Solution Approach 1:
The patent implements local quality by positioning a specific dielectric material (first dielectric material) only in regions where parasitic capacitance reduction is most beneficial, namely under and around source/drain regions. This localized approach reduces parasitic capacitance without requiring changes to the entire dielectric structure.
Solution Approach 2:
The composite dielectric structure uses two materials with different electrical properties. The first dielectric material has superior properties for reducing parasitic capacitance and is strategically placed where it provides maximum benefit, while the second dielectric material forms the main dielectric layer, creating a composite solution that addresses parasitic capacitance issues.
3Reliability
If a dielectric layer is deposited to prevent leakage, then leakage resistance improves, but the dielectric layer may be removed by subsequent etching and cleaning processes
Solution Approach 1:
The patent applies a preliminary protective action by depositing the first dielectric material (such as silicon nitride or silicon oxynitride) before subsequent etching and cleaning processes. This dielectric layer is specifically chosen for its high etching resistance, providing a protective barrier that prevents removal of underlying structures during manufacturing processes.
Solution Approach 2:
The patent uses a composite dielectric structure where the first dielectric material serves dual purposes: providing leakage prevention and offering etching resistance. The combination of first and second dielectric materials creates a structure where the first material protects the overall structure during manufacturing while the second material provides the primary dielectric function.
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 treated dielectric layer improves the integrity of the semiconductor device by minimizing leakage and parasitic capacitance, ensuring reliable performance and reducing the risk of void formation during subsequent epitaxial growth.
Implementation Method 1
performing a treatment process on the first dielectric layer
Data Source
AI summary
A method includes forming a gate stack over a semiconductor region, etching the semiconductor region to form a source/drain recess aside of the gate stack, depositing a first dielectric layer, wherein a portion of the first dielectric layer is in the source/drain recess, performing a treatment process on the first dielectric layer, depositing a second dielectric layer on the first dielectric layer, and etching the second dielectric layer and the first dielectric layer. A first portion of the first dielectric layer and a second portion of the second dielectric layer remain at a bottom of the source/drain recess to form a dielectric region. A source/drain region is deposited in the source/drain recess and over the dielectric region.