Rounded Nanoribbon Channels With Regrown Caps for Uniform Gate Deposition
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Solution Overview
Problem
Current nanoribbon-based transistors often have non-ideal shapes, leading to gaps between adjacent nanoribbons where the gate electrode is not formed, which reduces device performance due to residual sacrificial material and non-uniform nanoribbon thickness.
Innovation Solution
The nanoribbons are etched to produce rounded shapes, and additional channel material is grown over them, forming a cap or outer layer, allowing the gate dielectric and gate electrode to be deposited uniformly between nanoribbons, eliminating gaps and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional nanoribbon processing techniques are used, then nanoribbons can be formed, but they have non-ideal shapes with non-uniform thickness leading to gaps between adjacent nanoribbons
Solution Approach 1:
The nanoribbon cross-section is transformed from a non-uniform shape to a rounded shape with uniform thickness. The rounding process creates a curved profile that eliminates the non-ideal shape characteristics, ensuring consistent nanoribbon thickness throughout the cross-section and preventing gap formation between adjacent nanoribbons during gate electrode deposition.
2Ease of manufacture
If gate electrode is deposited around non-rounded nanoribbons, then gate structure can be formed, but gaps remain between adjacent nanoribbons where gate electrode is not formed
Solution Approach 1:
The nanoribbon cross-section is pre-rounded before gate electrode deposition to ensure that the subsequent gate material can be uniformly deposited around all nanoribbons. This preliminary shape modification prevents the formation of gaps between adjacent nanoribbons, ensuring complete gate electrode coverage and reliable device performance.
3Manufacturing precision
If additional channel material is grown over rounded nanoribbons, then outer layer is formed, but process complexity increases
Solution Approach 1:
Additional channel material is grown selectively over the rounded nanoribbon cross-section to form an outer layer. This local material addition enhances the nanoribbon structure where needed while maintaining the rounded profile, achieving superior thickness uniformity without requiring complete restructuring of the entire 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
The rounded nanoribbon channels enable complete deposition of gate materials, enhancing device performance by reducing columbic scattering and improving the overall functionality of nanoribbon-based transistors.
Implementation Method 1
The nanoribbons are etched to produce rounded shapes
Implementation Method 2
additional channel material is grown over the rounded nanoribbons, forming a cap or outer layer
Data Source
AI summary
Described herein are nanoribbon-based transistor devices in which the nanoribbons have rounded cross-sections. The nanoribbons may include caps or outer layers of semiconductor channel material grown over an inner layer of semiconductor channel material. Different materials may be used for the outer layers of NMOS and PMOS transistors. In one example, an integrated circuit device includes NMOS transistors formed from or more nanoribbons with rounded cross-sections and an outer layer of silicon, and a PMOS transistors formed from or more nanoribbons with rounded cross-sections and an outer layer of silicon germanium.