Vertical Field Effect Transistor With Two-Dimensional Channel Structure
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Solution Overview
Problem
Vertical field effect transistors (VFETs) with one-dimensional channel structures exhibit poor current drivability due to their relatively short channel width, limiting their performance compared to fin field effect transistors (FinFETs) and horizontal nanosheet field effect transistors (HNS FETs).
Innovation Solution
The design of VFETs with two-dimensional channel structures, featuring a channel shape with one or two first portions extending in a first direction and one or more second portions connected to the first portions in a different direction, surrounded by a gate structure, increases the effective channel width, enhancing electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a VFET uses a one-dimensional channel structure, then the device structure is simple and easy to manufacture, but the effective channel width is short resulting in poor current drivability
Solution Approach 1:
The patent transitions from a one-dimensional channel structure to a two-dimensional channel structure by adding lateral extensions that extend in multiple directions (first direction and second direction perpendicular to each other). This dimensional change increases the effective channel width while maintaining the vertical field effect transistor architecture, thereby improving current drivability without sacrificing manufacturing simplicity
2Device complexity
If a VFET uses a one-dimensional channel structure, then the device complexity is low, but the effective channel width is limited reducing electrical performance
Solution Approach 1:
The channel structure is designed with two-dimensional geometry featuring first portions extending in a first direction and second portions extending in a second direction perpendicular to the first direction. This dimensional expansion increases the effective channel width and improves electrical performance while adding only moderate structural complexity that can be integrated into existing VFET manufacturing processes
3Productivity
If a VFET increases channel width to improve current drivability, then the electrical performance improves, but the device structure becomes more complex
Solution Approach 1:
Instead of simply increasing channel width in one direction which would increase device area and complexity, the patent distributes the channel structure in two dimensions with portions extending in perpendicular directions. This approach increases the effective channel width for improved current drivability while maintaining a compact footprint and managing device complexity through efficient spatial arrangement
Data Source
AI summary
A vertical field effect transistor (VFET) including a first source/drain region, a channel structure upwardly protruding from the first source/drain region and configured to serve as a channel, the channel structure having a two-dimensional structure in a plan view, the channel structure having an opening at at least one side thereof, the channel structure including one or two first portions and one or more second portions, the one or two first portion extending in a first direction, and the one or more second portions connected to corresponding one or more of the one or more first portions and extending in a second direction, the second direction being different from the first direction, a gate structure horizontally surrounding the channel structure, and a second source/drain region upwardly on the channel structure may be provided.