Strained Fin Channel Devices via In-Situ Oxidation
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Solution Overview
Problem
Current methods for straining fin structures in semiconductor devices, such as finFETs, are ineffective in maintaining the necessary small strain levels required for improved performance, as the strain dissipates during the fabrication of source/drain structures, leading to inconsequential stress on the fin channels.
Innovation Solution
A method involving the formation of trenches and the use of an oxidizing filler material that exerts tensile stress on the fin structure, maintaining strain throughout the fabrication process without relying on embedded source/drain structures, which allows the fin to exhibit sustained tensile strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If embedded source/drain structures are used to strain the fin, then the fin structure is formed, but the strain dissipates during fabrication leading to inconsequential stress on the fin channel
Solution Approach 1:
The method applies strain to the fin structure before forming the source and drain regions. Trenches are etched into the substrate, filler material is deposited into the trenches, and the filler is oxidized in-situ to exert tensile stress on the fin. Only after this preliminary straining action is complete are the source and drain regions formed, ensuring the strain is already established and maintained throughout subsequent fabrication steps.
2Productivity
If the fin structure is strained to improve charge mobility, then performance is enhanced, but the strain level must be precisely maintained as small strain levels are required
Solution Approach 1:
The method changes the physical and chemical parameters of the filler material through oxidation. The filler material is deposited in a reduced state and then oxidized in-situ within the trenches, transforming its properties to exert the appropriate tensile stress on the fin. This parameter change allows precise control over the strain level applied to the fin channel, maintaining the small strain levels required for improved charge mobility without excessive stress.
3Ease of manufacture
If conventional straining methods are used, then the fabrication process is simple, but the strain is insufficient to maintain improved performance
Solution Approach 1:
The method introduces filler material as an intermediary element between the substrate and the fin structure. This filler material, when oxidized in-situ within the trenches, acts as a mediator that exerts controlled tensile stress on the fin channel. This intermediary approach maintains fabrication simplicity by using standard deposition and oxidation processes while achieving reliable performance improvement through sustained strain on the fin structure.
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 ensures that the fin structures experience a sustained small strain, enhancing charge mobility and maintaining improved performance in finFET and other fin channel devices, overcoming the limitations of existing strain methods.
Implementation Method 1
The embodiment oxidizes the filler in-place, the oxidizing causing a stress to be exerted on the first and second traverse sides of the fin, the stress causing the fin to exhibit a tensile strain in a lateral running direction of the fin
Data Source
AI summary
A semiconductor device is formed to include a fin structure, a first trench at a first lateral end of the fin, a second trench at a second lateral end of the fin, and a filler filled on a first traverse side of the fin and a second traverse side of the fin. The filler is contained between the first trench and the second trench, and oxidized in-place to cause a stress to be exerted on the first and second traverse sides of the fin, the stress causing the fin to exhibit a tensile strain in a lateral running direction of the fin.