High Surface Germanium Source Drain Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current integrated circuit fabrication processes face challenges in maintaining high germanium concentration in source or drain structures, leading to increased contact resistance and defects, especially during etching and downstream processing, which limits the scalability to sub-10 nanometer nodes.
Innovation Solution
In-situ epitaxial deposition of a thin, low germanium concentration boron-doped SiGe cap is used to protect high germanium PMOS source or drain structures from etching, allowing for higher germanium concentrations while reducing contact resistance through boron diffusion and selective etching techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high germanium concentration is used in source or drain structures, then channel strain is improved, but contact resistance increases and defects occur during etching
Solution Approach 1:
The source or drain structure is segmented into multiple regions with different germanium concentrations: a first region with lower germanium concentration and a second region with higher germanium concentration. This segmentation allows the structure to simultaneously achieve good contact properties in the first region and high channel strain in the second region, resolving the contradiction between contact resistance and channel strain.
Solution Approach 2:
Different regions of the source or drain structure are assigned different germanium concentrations according to their functional requirements. The first region has lower germanium concentration optimized for contact properties, while the second region has higher germanium concentration optimized for channel strain,实现ing local quality optimization throughout the structure.
2Strength
If high germanium concentration is used in source or drain structures, then channel strain is improved, but manufacturing precision deteriorates due to etching and downstream processing
Solution Approach 1:
The source or drain structure is divided into regions with different germanium concentrations, with the first region having lower germanium concentration that is more resistant to etching. This segmentation protects the overall structure from excessive germanium loss during manufacturing processes while maintaining high germanium concentration in the second region for channel strain.
Solution Approach 2:
The first region with lower germanium concentration acts as a protective buffer that withstands etching and downstream processing before the second region with high germanium concentration is exposed. This beforehand cushioning prevents premature germanium loss and maintains manufacturing precision throughout the fabrication process.
3Adaptability or versatility
If conventional fabrication processes are used for scaling, then current process compatibility is maintained, but scalability to sub-10 nanometer nodes is limited
Solution Approach 1:
The segmented source or drain structure with multiple germanium concentration regions can be integrated into existing fabrication processes while enabling advanced scaling. The different regions provide the necessary performance characteristics for sub-10 nanometer nodes, allowing conventional processes to be extended to smaller technology nodes.
Solution Approach 2:
By changing the germanium concentration parameter across different regions of the source or drain structure, the invention enables optimization for advanced technology nodes while maintaining compatibility with existing fabrication processes. This parameter variation allows scaling to sub-10 nanometer nodes without completely redesigning the fabrication 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 enables the use of high germanium concentrations above 55% in PMOS structures, improving contact resistance and maintaining channel strain, while minimizing defects and resistivity, thus facilitating the transition to smaller technology nodes.
Implementation Method 1
protect high germanium PMOS source or drain structures from etching
Implementation Method 2
reducing contact resistance through boron diffusion
Implementation Method 3
In-situ epitaxial deposition of a thin, low germanium concentration boron-doped SiGe cap
Data Source
AI summary
Integrated circuit structures having high surface germanium concentrations are described. In an example, an integrated circuit structure includes a fin having a lower fin portion and an upper fin portion. A gate stack is over the upper fin portion of the fin, the gate stack having a first side opposite a second side. A first source or drain structure has an epitaxial structure embedded in the fin at the first side of the gate stack. A second source or drain structure has an epitaxial structure embedded in the fin at the second side of the gate stack. Each of the epitaxial structures of the first and second source or drain structures includes silicon, germanium and boron, the germanium having an atomic concentration of greater than 55% at a top surface of each of the epitaxial structures of the first and second source or drain structures.