FinFET Stress-Inducing Spacers Prevent Channel Encroachment
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Solution Overview
Problem
The challenge in fabricating FinFET structures lies in forming stress-inducing source/drain regions with small dimensions, where the narrow spaces between gates limit the width of spacers, causing source/drain regions to encroach into channels and making it difficult to uniformly deposit stress-inducing materials, which can lead to device failure.
Innovation Solution
The method involves forming stress-inducing sidewall spacers about the fins and gate structures to induce stress within the channels, allowing for the precise implantation of conductivity-determining ions to create source and drain regions without encroachment, while also using opposite stress-inducing spacers to enhance carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the width of source/drain-forming spacers is reduced to accommodate smaller gate pitch, then device integration density is improved, but source/drain regions encroach into channels causing device failure
Solution Approach 1:
The patent forms stress-inducing spacers before source/drain region formation. These pre-formed spacers define precise boundaries that prevent source/drain regions from encroaching into channels during subsequent processing steps, while still allowing high device integration density through optimized spacer dimensions and materials
2Productivity
If the area between parallel gates is reduced to increase gate density, then device integration is improved, but uniform deposition of stress-inducing material becomes difficult
Solution Approach 1:
The patent applies stress-inducing materials locally in the source/drain regions adjacent to channels, rather than requiring uniform deposition across the entire gate area. This localized approach allows high gate density while ensuring stress-inducing material is precisely where needed for carrier mobility enhancement
3Reliability
If stress-inducing materials are used to increase carrier mobility, then device performance is improved, but the small dimensions of FinFET features make it difficult to uniformly deposit adequate amounts
Solution Approach 1:
The patent uses stress-inducing spacers as intermediary structures that deliver stress to the channel region. These spacers act as mediators between the deposition process and the channel, enabling controlled stress transfer without requiring direct uniform deposition of large amounts of stress-inducing material across difficult-to-reach areas
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 enables the fabrication of scalable FinFET structures with stress-inducing source/drain regions that prevent channel encroachment and improve carrier mobility, resulting in enhanced device performance by efficiently utilizing the limited space between gates.
Implementation Method 1
Stress-inducing sidewall spacers are formed about the sidewalls of the plurality of parallel fins and the sidewalls of the gate structure. The stress-inducing sidewall spacers induce a stress within the channels.
Implementation Method 2
First conductivity-determining ions are implanted into the plurality of parallel fins using the stress-inducing sidewall spacers and the gate structure as an implantation mask to form source and drain regions within the plurality of parallel fins.
Data Source
AI summary
Methods for fabricating FinFET structures with stress-inducing source/drain-forming spacers and FinFET structures having such spacers are provided herein. In one embodiment, a method for fabricating a FinFET structure comprises fabricating a plurality of parallel fins overlying a semiconductor substrate. Each of the fins has sidewalls. A gate structure is fabricated overlying a portion of each of the fins. The gate structure has sidewalls and overlies channels within the fins. Stress-inducing sidewall spacers are formed about the sidewalls of the fins and the sidewalls of the gate structure. The stress-inducing sidewall spacers induce a stress within the channels. First conductivity-determining ions are implanted into the fins using the stress-inducing sidewall spacers and the gate structure as an implantation mask to form source and drain regions within the fins.