Source/Drain Liner Structure to Suppress Dopant Diffusion
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Solution Overview
Problem
As semiconductor devices undergo miniaturization, the reduction in minimum feature size leads to increased dopant diffusion from source/drain regions into channel regions, which hampers channel mobility and device performance.
Innovation Solution
Epitaxially grown source/drain regions with liner layers composed of a semiconductor material containing a blocker element, such as carbon, are used to reduce dopant diffusion, thereby enhancing channel mobility and device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If minimum feature size is reduced to increase integration density, then more components can be integrated into a given area, but dopant diffusion from source/drain regions into channel regions increases
Solution Approach 1:
A liner layer composed of a semiconductor material containing a blocker element (such as carbon) is introduced as an intermediary between the source/drain regions and the channel region. This liner layer acts as a diffusion barrier that prevents dopants from the source/drain regions from diffusing into the channel region, thereby resolving the contradiction between increased integration density and maintained channel mobility.
Solution Approach 2:
The liner layer is formed using a composite semiconductor material that incorporates a blocker element (such as carbon) within the semiconductor matrix. This composite material structure provides both the semiconductor functionality required for device operation and the diffusion barrier properties needed to prevent dopant contamination, thus allowing high integration density without sacrificing channel mobility.
2Productivity
If minimum feature size is reduced to increase integration density, then more components can be integrated into a given area, but device performance deteriorates due to dopant diffusion
Solution Approach 1:
The liner layer serves as a protective intermediary that isolates the channel region from dopant diffusion, ensuring that device performance is maintained even as integration density increases through feature size reduction.
Solution Approach 2:
The use of composite semiconductor materials with blocker elements in the liner layer enables the structure to simultaneously achieve the electrical performance required for high-density integration and the diffusion barrier properties necessary for maintaining device performance.
3Reliability
If epitaxially grown source/drain regions with liner layers are used to reduce dopant diffusion, then channel mobility increases, but device complexity increases
Solution Approach 1:
The liner layer is applied locally only at the critical interface between the source/drain regions and the channel region, rather than throughout the entire device structure. This localized approach provides the necessary diffusion barrier to maintain channel mobility while minimizing the overall structural complexity and avoiding unnecessary modifications to other parts of the device.
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 use of epitaxially grown source/drain regions with liner layers effectively reduces dopant diffusion into channel regions, leading to increased channel mobility and improved device performance by suppressing out-diffusion of dopants.
Implementation Method 1
liner layers composed of a semiconductor material containing a blocker element, such as carbon, are used to reduce dopant diffusion
Implementation Method 2
reduction in minimum feature size leads to increased dopant diffusion from source/drain regions into channel regions
Implementation Method 3
Epitaxially grown source/drain regions with liner layers
Data Source
AI summary
In an embodiment, a device includes: a first nanostructure; a source/drain region adjoining a first channel region of the first nanostructure, the source/drain region including: a main layer; and a first liner layer between the main layer and the first nanostructure, a carbon concentration of the first liner layer being greater than a carbon concentration of the main layer; an inter-layer dielectric on the source/drain region; and a contact extending through the inter-layer dielectric, the contact connected to the main layer, the contact spaced apart from the first liner layer.