Gate-All-Around Transistors Using 2D Material on Dielectric Mandrel
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Solution Overview
Problem
Nanosheet field-effect transistors face challenges in scaling due to quantum confinement and short channel effects, which limit their performance and packing density in integrated circuits.
Innovation Solution
A field-effect transistor structure is developed using a mandrel composed of dielectric material with a gate electrode wrapped around its sides, and a channel layer made of two-dimensional material, allowing for improved electrostatic control and increased packing density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nanosheet thickness is reduced to increase packing density, then device integration density improves, but quantum confinement degrades performance
Solution Approach 1:
The patent changes the material parameter from conventional semiconductor to two-dimensional material, which fundamentally alters the quantum confinement behavior. This allows maintaining atomic-layer thickness (improving packing density) while avoiding performance degradation through the unique electronic properties of 2D materials that differ from bulk semiconductor physics.
2Length of moving object
If gate length is shrunk to improve device scaling, then integration density increases, but short channel effects limit further scaling
Solution Approach 1:
The patent transitions from planar gate control to gate-all-around three-dimensional configuration. The gate electrode completely surrounds the channel region, providing electrostatic control from all directions including the bottom, which dramatically improves control efficiency and enables continued scaling to shorter gate lengths by adding a vertical control dimension.
Solution Approach 2:
The patent employs a composite structure combining two-dimensional channel material with dielectric mandrel and gate electrode materials. This composite approach allows the channel to be fully surrounded by gate control structures while maintaining the unique electrical properties of 2D materials, achieving superior electrostatic control for short channel devices.
3Ease of manufacture
If conventional nanosheet structures are used, then fabrication is straightforward, but scaling limits are reached due to quantum confinement and short channel effects
Solution Approach 1:
The patent forms the two-dimensional material channel layer on the mandrel structure before creating the gate electrodes. This preliminary formation of the channel with predetermined thickness and positioning enables subsequent gate-all-around fabrication without requiring complex post-processing to achieve the desired channel dimensions, maintaining ease of manufacture while enabling advanced scaling.
Data Source
AI summary
Structures for a field-effect transistor and methods of forming structures for a field-effect transistor. A gate electrode has a section that is wrapped about a first side surface and a second side surface of a mandrel that is composed of a dielectric material. A channel layer has a channel region that is positioned in part between the first side surface of the mandrel and the section of the gate electrode. The channel layer is composed of a two-dimensional material.