Single Diffusion Break Structure for Protecting Source/Drain Regions
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Solution Overview
Problem
The challenge in semiconductor fabrication is the difficulty in creating small feature spacings and maintaining device performance due to damage and defects in epitaxial source/drain regions during the removal of dummy gates, leading to increased contact resistance and degraded performance.
Innovation Solution
A single diffusion break structure is introduced, filled with an insulator material and lined with a liner material, which protects the epitaxial source/drain regions during the removal of dummy gates by extending into the substrate and using specific deposition and etching processes to maintain the integrity of these regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dummy gate structures are removed to create single diffusion breaks, then diffusion region separation is achieved, but epitaxial source and drain regions are damaged or removed
Solution Approach 1:
A liner material is deposited on the trench walls before the deep trench etch process removes the dummy gate. This preliminary protective action prevents the etch process from damaging the epitaxial source and drain regions while still allowing the dummy gate to be removed for single diffusion break formation.
Solution Approach 2:
The liner material acts as an intermediary layer between the deep trench etch process and the epitaxial source/drain regions. It mediates the harmful interaction by providing a protective barrier that allows the etch to proceed without directly contacting and damaging the sensitive epitaxial regions.
2Ease of manufacture
If deep trench etch is used to remove dummy gates, then single diffusion break is formed, but source/drain epitaxial volume is reduced
Solution Approach 1:
The liner material is deposited in advance to protect the epitaxial regions during the deep trench etch process, preventing volume loss that would otherwise occur during the aggressive etching required to form the single diffusion break.
3Ease of manufacture
If dummy gates are removed for single diffusion breaks, then diffusion separation is achieved, but contact resistance increases
Solution Approach 1:
The liner material is deposited before the dummy gate removal process to protect the epitaxial source and drain regions. This protection maintains the full contact area between the metal contacts and the epitaxial regions, preventing the increase in contact resistance that would result from etch-induced damage or volume reduction.
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 preserves the source/drain volume and contact area, reducing defects and maintaining device performance even at smaller technology nodes like 10 nm and below.
Implementation Method 1
depositing liner material on sidewalls of the sidewalls of the trench including in the undercut region
Implementation Method 2
filling the trench with insulator material
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to single diffusion cut for gate structures and methods of manufacture. The structure includes a single diffusion break extending into a substrate between diffusion regions of adjacent gate structures, the single diffusion break filled with an insulator material and further comprising an undercut region lined with a liner material which is between the insulator material and the diffusion regions.