V-Shaped Epitaxial Layer Stress Induction in MOS Transistors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for forming epitaxial layers in semiconductor devices to induce stress in MOS transistors are inefficient, affecting device performance by not achieving satisfactory stress levels.
Innovation Solution
A method involving forming a first gate structure, etching a recess, performing ion implantation to create an amorphous layer, removing it, and growing an epitaxial layer in the recess, resulting in a V-shaped epitaxial layer connected to a bump with inclined sidewalls, which enhances stress and volume, improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional selective epitaxial growth (SEG) technique is used to form epitaxial structure, then the process is simple and easy to manufacture, but the stress induced in the channel region is insufficient, affecting device performance
Solution Approach 1:
The fabrication process is divided into multiple distinct stages: forming gate structure, creating recesses, ion implantation to form amorphous layer, removing amorphous layer, and epitaxial growth. This segmentation allows each step to be optimized independently, achieving high stress induction while maintaining manufacturing feasibility through systematic process breakdown
Solution Approach 2:
Ion implantation is performed in advance to create an amorphous layer that serves as a foundation for subsequent epitaxial growth. This preliminary action prepares the substrate in a controlled manner, ensuring that the epitaxial layer forms with the desired stress characteristics and structural integrity
2Speed
If epitaxial layer is formed to increase carrier mobility, then transistor speed is improved, but the stress induction is insufficient with current methods, requiring enhanced fabrication approaches
Solution Approach 1:
The method changes multiple process parameters including ion implantation energy and dose, etching conditions, and epitaxial growth parameters. By systematically adjusting these parameters, the epitaxial layer is formed with optimized stress characteristics that enhance carrier mobility and transistor speed while ensuring reliable stress induction
Solution Approach 2:
The amorphous layer formed through ion implantation serves as an intermediary structure between the substrate and the epitaxial layer. This intermediate layer facilitates controlled stress transfer and ensures proper integration, thereby improving both the effectiveness of stress induction and the overall reliability of the device
3Volume of moving object
If V-shaped epitaxial layer with bump structure is formed, then stress and volume are enhanced, but the fabrication process becomes more complex with multiple etching and implantation steps
Solution Approach 1:
The invention transitions from conventional planar epitaxial layers to a three-dimensional V-shaped structure with a bump. This dimensional change increases the epitaxial layer volume and stress induction capability. The complex shape is achieved through coordinated ion implantation and selective etching processes that work together to create the desired geometry
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 allows for the formation of epitaxial layers with increased stress and volume, enhancing the performance of semiconductor devices by improving carrier mobility and transistor speed.
Implementation Method 1
performing an ion implantation process to form an amorphous layer directly under the recess
Implementation Method 2
forming an epitaxial layer in the recess
Data Source
AI summary
A method for fabricating semiconductor device includes the steps of: forming a first gate structure on a substrate; performing a first etching process to form a recess adjacent to the first gate structure; performing an ion implantation process to form an amorphous layer directly under the recess; performing a second etching process to remove the amorphous layer; and forming an epitaxial layer in the recess.