Semiconductor Source/Drain Structures with Graded Germanium
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Solution Overview
Problem
As semiconductor devices continue to shrink in size, challenges arise in integrating electronic components efficiently while maintaining performance and reducing manufacturing complexities.
Innovation Solution
A method involving the formation of a multilayer stack with alternating semiconductor layers, patterning fins and trenches, and epitaxial growth of source/drain structures with varying germanium concentrations to enhance device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If minimum feature size is reduced to increase integration density, then more components can be integrated into a given area, but manufacturing precision and device performance deteriorate
Solution Approach 1:
The patent applies local quality by creating regions with different germanium concentrations within the source/drain structures. The first source/drain structure has a first germanium concentration while the second source/drain structure has a second germanium concentration, allowing localized optimization of material properties to maintain manufacturing precision while achieving high integration density
Solution Approach 2:
The patent utilizes parameter changes by varying the germanium concentration parameter in the source/drain structures. By controlling the germanium concentration to be different between the first and second source/drain structures, the invention optimizes device performance and maintains precision despite reduced minimum feature sizes
2Quantity of substance
If minimum feature size is reduced to increase integration density, then more components can be integrated into a given area, but device performance deteriorates
Solution Approach 1:
The patent implements local quality by creating non-uniform germanium concentration distributions in the source/drain regions. This allows different portions of the device to have optimized material properties for their specific functional requirements, thereby maintaining device performance despite increased integration density
Solution Approach 2:
The patent employs composite materials by combining regions with different germanium concentrations in the source/drain structures. This composite approach allows the device to benefit from the advantageous properties of each material region, maintaining performance while achieving higher integration density
3Ease of manufacture
If conventional source/drain structures are used, then manufacturing is simpler, but strain effects are insufficient and short channel effects increase
Solution Approach 1:
The patent applies local quality by creating source/drain structures with non-uniform germanium concentrations that are specifically optimized for their location and function within the device. This localized material optimization enhances strain effects and reduces short channel effects while maintaining manufacturing feasibility
Solution Approach 2:
The patent utilizes parameter changes by varying the germanium concentration parameter across different source/drain structures. This parameter optimization is specifically tailored to address strain effects and short channel effects, improving device reliability while keeping the manufacturing process manageable
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
Enhances integration density and reduces manufacturing complexity by allowing for improved strain effects and reduced short channel effects in semiconductor devices.
Implementation Method 1
epitaxial growth of source/drain structures with varying germanium concentrations
Data Source
AI summary
Semiconductor devices and methods of fabrication are described herein. The method includes steps for patterning fins in a multilayer stack and forming an opening in a fin and into a substrate as an initial step in forming a source/drain region. A first semiconductor material is epitaxially grown from channels exposed along sidewalls of the opening to form first source/drain structures. A second semiconductor material is epitaxially grown from the first semiconductor material to form a second source/drain structure over and to fill a space between the first source/drain structures. A bottom of the second source/drain structure is located below a bottommost surface of the first source/drain structures. The second semiconductor material has a greater concentration percentage by volume of germanium than the first semiconductor material. A stack of nanostructures is formed by removing sacrificial layers of the multilayer stack, the second semiconductor material being electrically coupled to the nanostructures.