Vertical Gate All-Around Device Channel Straining
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Solution Overview
Problem
Conventional channel straining techniques for planar devices are incompatible with vertical gate all-around (VGAA) devices, which hinders the enhancement of charge carrier mobility in these devices.
Innovation Solution
A method and structure for introducing strain into VGAA devices by selectively etching the channel structure to form vertically extending gaps and filling them with gap-filling materials that generate lateral strains, aligning with the vertical channel direction, thereby enhancing carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional channel straining techniques for planar devices are used, then charge carrier mobility can be enhanced in planar devices, but these techniques are incompatible with vertical gate all-around devices
Solution Approach 1:
The patent transitions from planar (2D) channel straining techniques to a vertical (3D) channel straining approach. By introducing vertically extending gaps and filling them with stressor materials, the invention creates strain in the vertical channel direction, enabling mobility enhancement in VGAA devices while maintaining compatibility with the three-dimensional device architecture
Solution Approach 2:
The patent applies strain locally to the vertical channel region by selectively etching gaps in specific locations and filling them with stressor materials. This localized approach creates targeted tensile or compressive strain in the channel structure, enhancing carrier mobility in the vertical direction without affecting other device regions
2Reliability
If vertically extending gaps are etched and filled with stressor materials, then charge carrier mobility is enhanced in VGAA devices, but device structure complexity increases
Solution Approach 1:
The patent segments the vertical channel structure by introducing vertically extending gaps that divide the channel into separate regions. These gaps are then filled with stressor materials, creating a segmented structure with alternating channel and stressor regions. This segmentation enables localized strain application while maintaining overall device functionality
Solution Approach 2:
The patent implements a nested structure where stressor materials are placed within vertically extending gaps that are themselves within the larger vertical channel structure. The stressor materials are nested inside the channel region, creating a multi-layered configuration that integrates strain enhancement within the existing device architecture
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 boosts the charge carrier mobility in VGAA devices by applying suitable tensile or compressive strains along the vertical channel direction, improving device performance and compatibility with existing fabrication technologies.
Implementation Method 1
the stressor affects lateral strain in the channel structure, thereby straining the channel in the vertical channel direction
Data Source
AI summary
Method and structure for enhancing channel performance in a vertical gate all-around device, which provides a device comprising: a source region; a drain region aligned substantially vertically to the source region; a channel structure bridging between the source region and the drain region and defining a substantially vertical channel direction; and a gate structure arranged vertically between the source region and the drain region and surrounding the channel structure. The channel structure comprises a plurality of channels extending substantially vertically abreast each other, each bridging the source region and the drain region, and at least one stressor interposed between each pair of adjacent channels and extending substantially along the vertical channel direction; the stressor affects lateral strain on the adjacent channels, thereby straining the channels in the vertical channel direction.