Stacked GAA Channel Layout for Higher Drive Current
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Solution Overview
Problem
As integrated circuit (IC) density continues to scale, gate-all-around (GAA) devices face challenges in increasing drive current while maintaining gate control and mitigating short-channel effects.
Innovation Solution
The proposed solution involves fabricating multigate devices with at least two sheet-like channel layers connected by a channel connecting portion, which allows for increased current conduction areas and higher drive currents compared to conventional GAA devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional GAA device structures are used, then gate control and short-channel effect mitigation are maintained, but drive current increases are limited due to scaling constraints
Solution Approach 1:
The channel is divided into multiple discrete sheet-like layers stacked vertically, with each layer providing independent conduction paths. This segmentation allows the drive current to be increased by adding more parallel conduction paths without increasing the lateral footprint, thereby improving power performance while managing device complexity through vertical stacking rather than lateral expansion.
Solution Approach 2:
The invention transitions from a conventional planar channel structure to a vertically stacked three-dimensional channel architecture. By moving the conduction paths into the vertical dimension through multiple stacked sheets, the device achieves higher drive current without proportionally increasing device complexity, as the vertical stacking allows for compact integration within the same lateral footprint.
2Productivity
If IC density continues to scale down, then production efficiency improves and costs decrease, but gate control and short-channel effects become more difficult to manage
Solution Approach 1:
The channel is divided into multiple discrete sheet-like layers stacked vertically, with each layer providing independent conduction paths. This segmentation allows the drive current to be increased by adding more parallel conduction paths without increasing the lateral footprint, thereby improving power performance while managing device complexity through vertical stacking rather than lateral expansion.
Solution Approach 2:
The invention transitions from a conventional planar channel structure to a vertically stacked three-dimensional channel architecture. By moving the conduction paths into the vertical dimension through multiple stacked sheets, the device achieves higher drive current without proportionally increasing device complexity, as the vertical stacking allows for compact integration within the same lateral footprint.
Data Source
AI summary
Multi-gate devices and methods for fabricating such are disclosed herein. An exemplary device includes a channel layer, a first source/drain feature, a second source/drain feature, and a metal gate. The channel layer has a first horizontal segment, a second horizontal segment, and a vertical segment connects the first horizontal segment and the second horizontal segment. The first horizontal segment and the second horizontal segment extend along a first direction, and the vertical segment extends along a second direction. The vertical segment has a width along the first direction and a thickness along the second direction, and the thickness is greater than the width. The channel layer extends between the first source/drain feature and the second source/drain feature along a third direction. The metal gate wraps channel layer. In some embodiments, the first horizontal segment and the second horizontal segment are nanosheets.