Fin Spacer E-Beam Charging for Epitaxial Growth Control
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Solution Overview
Problem
In the semiconductor industry, particularly for fin field-effect transistors (FinFETs), there is a challenge in preventing the undesired merging of epitaxial structures over semiconductor fins, which affects device performance and requires precise control of epitaxial growth to maintain separate source/drain regions.
Innovation Solution
The method involves forming fin spacers on semiconductor fins and performing an electron-beam (e-beam) treatment on specific fin spacers to charge them, which then influence the growth of epitaxial structures, preventing their merging by adjusting the growth rate and size of N-type and P-type epitaxial structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epitaxial growth is performed to form source/drain regions, then device density and performance are improved, but undesired merging of epitaxial structures occurs affecting device performance
Solution Approach 1:
The patent applies preliminary anti-action by performing e-beam treatment on fin spacers before epitaxial growth to pre-charge them with negative charges. This preliminary charging creates an electric field that actively repels positively charged epitaxial materials during subsequent growth, preventing the merging issue before it can occur. The negative charges are implanted at specific doses (1E12 to 1E14 ions/cm²) to create sufficient repulsive force against the incoming epitaxial material.
Solution Approach 2:
The fin spacers serve as an intermediary element between the semiconductor fins and the epitaxial structures. By charging the fin spacers through e-beam treatment, they become active mediators that control the growth and separation of epitaxial structures. The charged fin spacers create an electric field barrier that prevents direct contact and merging of adjacent epitaxial regions, thus mediating the interaction between competing growth forces.
2Manufacturing precision
If e-beam treatment is applied to fin spacers to prevent merging, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
The e-beam treatment step serves multiple functions simultaneously: it charges the fin spacers to prevent epitaxial merging, it defines the lateral boundaries of source/drain regions, and it provides selective control over growth in different device regions. This multi-functionality reduces the need for additional separate process steps, thereby limiting the increase in process complexity despite adding the e-beam treatment.
Solution Approach 2:
The patent utilizes parameter changes in the e-beam treatment process to achieve different outcomes: by adjusting electron beam dose (1E12 to 1E14 ions/cm²), energy (50 eV to 0.5 keV), and exposure patterns, the same e-beam step can control various aspects of epitaxial growth. This parameter-based control allows a single process step to manage multiple critical dimensions, reducing overall process 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 effectively prevents the merging of epitaxial structures, ensuring separate and distinct source/drain regions, thereby improving device performance and reducing fabrication costs through increased throughput.
Implementation Method 1
An e-beam treatment is performed on the fin spacer
Implementation Method 2
performing an electron-beam (e-beam) treatment on specific fin spacers to charge them
Implementation Method 3
which then influence the growth of epitaxial structures, preventing their merging
Data Source
AI summary
A method for manufacturing a semiconductor device includes forming a semiconductor fin over a substrate. A fin spacer is formed on a sidewall of the semiconductor fin. An e-beam treatment is performed on the fin spacer. An epitaxial structure is formed over the semiconductor fin. The epitaxial structure is in contact with the e-beam treated fin spacer.