Comb-Shaped Transistor Device for Drive Current Enhancement
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Solution Overview
Problem
Current field effect transistor (FET) devices face limitations in increasing drive current while maintaining device size, as they either rely on horizontal current flow or vertical fin structures, which do not efficiently utilize the semiconductor material for enhanced performance.
Innovation Solution
A comb-shaped transistor device is fabricated by forming alternating sacrificial spacer segments and channel segments on a substrate, creating channel sidewalls and dividing them into sacrificial and channel slabs to form comb-like structures, which are then trimmed to create nanosheet columns with source/drains, combining aspects of fin FETs and nanosheet transistors for increased drive current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional horizontal current flow FET structures are used, then device simplicity is maintained, but drive current capacity is limited
Solution Approach 1:
The channel is divided into multiple vertical segments or fins that extend upward from the substrate, with each fin acting as an independent current conduction path. This segmentation increases the total effective channel width and drive current capacity while maintaining a relatively simple planar footprint.
Solution Approach 2:
The channel structure transitions from a two-dimensional planar configuration to a three-dimensional vertical fin structure. Current flows vertically through multiple fin channels, utilizing the vertical dimension to increase effective channel width and drive current without increasing the device footprint area.
2Power
If FinFET vertical structures are used, then channel width utilization is improved, but manufacturing complexity increases
Solution Approach 1:
The FinFET structure divides the channel into multiple vertical fins, each contributing to the total drive current. This segmentation allows incremental increases in drive current capacity by adding more fins rather than requiring a single large-width channel, simplifying the manufacturing approach.
Solution Approach 2:
Multiple fin structures are combined within a single device footprint to achieve high drive current capacity. The fins are manufactured using the same process steps, merging their fabrication into a unified structure that achieves high performance without proportionally increasing manufacturing complexity.
3Power
If channel width is increased to enhance drive current, then drive current capacity is improved, but device area increases
Solution Approach 1:
The channel structure utilizes the vertical dimension by forming fins that extend upward from the substrate. This allows the effective channel width to be increased without proportionally increasing the planar footprint area, as multiple fins can be packed vertically within a compact device footprint.
Solution Approach 2:
The channel is segmented into multiple vertical fins that can be densely packed within a small footprint. Each fin contributes to the total drive current capacity, allowing the device to achieve high current capacity while maintaining a compact area through efficient vertical space utilization.
Data Source
AI summary
A method of forming a comb-shaped transistor device is provided. The method includes forming a stack of alternating sacrificial spacer segments and channel segments on a substrate. The method further includes forming channel sidewalls on opposite sides of the stack of alternating sacrificial spacer segments and channel segments, and dividing the stack of alternating sacrificial spacer segments and channel segments into alternating sacrificial spacer slabs and channel slabs, wherein the channel slabs and channel sidewalls form a pair of comb-like structures. The method further includes trimming the sacrificial spacer slabs and channel slabs to form a nanosheet column of sacrificial plates and channel plates, and forming source/drains on opposite sides of the sacrificial plates and channel plates.