SRAM FinFETs with Varying Fin Widths for Contact Area
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Solution Overview
Problem
The semiconductor industry faces challenges in fabricating high-density, high-performance SRAM cells using fin field effect transistors (FinFETs) due to complexities in manufacturing processes, particularly in forming reliable source/drain contacts and gate structures with high-k dielectric materials, which affect device performance and density.
Innovation Solution
The proposed solution involves the use of epitaxial source/drain structures and a specific layout configuration of fin structures and gate electrodes in SRAM cells, where fin structures of varying widths are used to increase the contact area between epitaxial source/drain regions and bar contacts, enhancing current flow and controlling short channel effects through precise recess etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional FinFET manufacturing processes are used, then device density and performance are improved, but manufacturing complexity and difficulty increase
Solution Approach 1:
The patent segments the FinFET structure into multiple fins within a single gate, allowing each fin to be independently formed and controlled. This segmentation enables complex device functionality while maintaining manageable manufacturing processes by breaking down the overall structure into repeatable units
Solution Approach 2:
The patent employs nested structures where multiple fins are nested within a common gate structure, and source/drain regions are nested between the fins. This nesting approach increases device density without proportionally increasing manufacturing complexity by sharing common structural elements
2Area of moving object
If standard fin structures are used, then manufacturing is simpler, but contact area between source/drain and bar contacts is insufficient
Solution Approach 1:
The patent applies local quality by varying the widths of individual fins to optimize contact area at specific locations. The first fin has a different width than the second fin, allowing tailored contact areas for different source/drain regions while maintaining overall manufacturing simplicity through a standardized multi-fin approach
Solution Approach 2:
The patent transitions from a single-fin structure to a multi-fin structure, adding spatial dimensionality to increase contact area. By arranging multiple fins side-by-side under a common gate, the total contact area between source/drain regions and bar contacts is significantly increased without complicating the fundamental manufacturing process
3Reliability
If high-k dielectric materials are used in gate structures, then device performance is improved, but manufacturing reliability decreases
Solution Approach 1:
The patent employs composite gate structures combining high-k dielectric materials with metal layers. This composite approach enables the use of high-k materials for improved device performance while managing manufacturing reliability through established composite material processing techniques and optimized layer configurations
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 results in improved current performance and reduced short channel effects by increasing the contact area between epitaxial source/drain structures and bar contacts, enabling more efficient manufacturing of high-density SRAM cells with enhanced performance.
Implementation Method 1
sources and drains are formed by using an epitaxial growth method
Data Source
AI summary
In a method of manufacturing a semiconductor device, a first fin structure, a second fin structure and a third fin structure, which extend in a first direction, are formed over a substrate. A first gate structure is formed over the first to third fin structures. The first gate structure extends in a second direction crossing the first direction. The first fin structure and the second fin structure are arranged adjacent to each other, and widths of the first and second fin structures in the second direction are smaller than a width of the third fin structure in the second direction.