Epitaxial Fin Structure With Buffer and Cap for Contact-Volume Balance
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Solution Overview
Problem
The complexity of semiconductor manufacturing processes is increased by the demand for smaller semiconductor devices, such as MOSFETs and finFETs, which requires improved methods to balance the dimensions of contact areas and volume of fin structures in integrated circuits.
Innovation Solution
The fabrication method involves forming epitaxial fin structures with epitaxial buffer and capping regions to enhance the trade-off between contact areas and volume, using epitaxial growth processes like CVD and SEG to create strained semiconductor materials with varying dopant concentrations and geometries, and incorporating merged and unmerged fin structures to optimize device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dimensions of semiconductor devices are scaled down to increase storage capacity and processing speed, then device performance is improved, but manufacturing complexity increases
Solution Approach 1:
The fin structure is divided into multiple epitaxial regions with different compositions and properties. The merged fin structure combines multiple fins into a unified structure, allowing independent optimization of different regions while simplifying the overall manufacturing process by reducing the number of separate structures that need to be fabricated
Solution Approach 2:
Different epitaxial regions are created with varying material compositions (e.g., SiGe vs Si) and dopant concentrations tailored to specific functional requirements. The merged fin structure allows different regions to have optimized local properties for carrier mobility, contact resistance, and stress management, while maintaining overall device performance
2Reliability
If the contact area is increased to improve device performance, then carrier mobility is enhanced, but the volume of fin structures must be reduced to maintain scaling
Solution Approach 1:
The merged fin structure transitions from discrete separate fins to a continuous three-dimensional structure, effectively utilizing vertical and lateral dimensions simultaneously. This allows the contact area to be expanded across the merged structure surface while the overall volume is controlled by the compact integration of multiple fins into a unified structure
Solution Approach 2:
Multiple fin structures are nested and merged into a single unified structure, where individual fins are integrated within the overall merged fin geometry. This nesting approach allows the contact area to encompass multiple fin surfaces while the volume is efficiently utilized through the compact nested arrangement
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 improves the balance between contact area and volume, enhancing carrier mobility and device performance while reducing manufacturing complexity, particularly in finFETs used as pull-up transistors in SRAM bit cells.
Implementation Method 1
epitaxial growth processes like CVD and SEG to create strained semiconductor materials
Implementation Method 2
epitaxial growth processes like CVD and SEG
Implementation Method 3
create strained semiconductor materials with varying dopant concentrations
Data Source
AI summary
A fin structure on a substrate is disclosed. The fin structure can comprises a first epitaxial region and a second epitaxial region separated by a dielectric region, a merged epitaxial region on the first epitaxial region and the second epitaxial region, an epitaxial buffer region on a top surface of the merged epitaxial region, and an epitaxial capping region on the buffer epitaxial region and side surfaces of the merged epitaxial region.