Semiconductor Nanoribbon Composition Gradient for Intrinsic Compressive Strain
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Solution Overview
Problem
Existing transistor architectures face challenges in maintaining sufficient strain on semiconductor channels, particularly in gate-all-around and forksheet configurations, leading to poor device performance as scaling down in integrated circuits becomes more difficult.
Innovation Solution
Intrinsic strain is induced in semiconductor nanoribbons by altering the material composition along their length, such as creating a germanium or tin concentration gradient, using annealing processes to drive germanium or tin inward, resulting in thinner nanoribbons with higher germanium or tin concentration in the central portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gate-all-around and forksheet architectures are used to maximize semiconductor surface area, then transistor density is improved, but sufficient strain on semiconductor channels cannot be maintained
Solution Approach 1:
The patent applies local quality by creating a composition gradient within the nanoribbon channel, where the germanium concentration varies spatially along the channel length. This gradient structure provides different local properties: higher germanium concentration in certain regions to induce compressive strain, and lower concentration in other regions to maintain carrier mobility, thereby resolving the contradiction between achieving sufficient strain and maintaining device performance in gate-all-around architectures
2Stress or pressure
If external strain from gate structures or diffusion regions is used, then strain on semiconductor channels is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent implements self-service by enabling the nanoribbon channel itself to generate the required compressive strain through its intrinsic composition gradient, rather than relying on external strain from gate structures or diffusion regions. The material composition variation within the nanoribbon automatically produces the strain field needed for enhanced device performance, simplifying the overall device structure and manufacturing process
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
This approach enhances device performance by imparting compressive strain intrinsically, especially beneficial for PMOS devices, improving transistor performance and transistor density without relying on external strain from gate structures or diffusion regions.
Implementation Method 1
annealed to drive the germanium or tin inwards along a portion of the semiconductor nanoribbons thus increasing the germanium or tin concentration through a central portion
Data Source
AI summary
Techniques are provided herein to form semiconductor devices having strained channel regions. In an example, semiconductor nanoribbons of silicon germanium (SiGe) or germanium tin (GeSn) may be formed and subsequently annealed to drive the germanium or tin inwards along a portion of the semiconductor nanoribbons thus increasing the germanium or tin concentration through a central portion along the lengths of the one or more nanoribbons. Specifically, a nanoribbon may have a first region at one end of the nanoribbon having a first germanium concentration, a second region at the other end of the nanoribbon having substantially the same first germanium concentration (e.g., within 5%), and a third region between the first and second regions having a second germanium concentration higher than the first concentration. A similar material gradient may also be created using tin. The change in material composition (gradient) along the nanoribbon length imparts a compressive strain.