Semiconductor Source Drain Contacts with Selective Epitaxial Growth
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Solution Overview
Problem
The operating characteristics of semiconductor devices, particularly MOSFETs, deteriorate as they are scaled down, leading to inefficiencies in contact area and resistance, which affects the performance of integrated circuits.
Innovation Solution
The semiconductor device incorporates a source/drain contact that extends across selective epitaxial growth portions on active patterns, with varying distances and heights, and includes inclined edge surfaces to increase contact area and reduce resistance, thereby improving electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If MOSFETs are scaled down to increase integration density, then device size is reduced, but contact area decreases and contact resistance increases
Solution Approach 1:
The contact structure extends vertically into recess regions between active patterns, transitioning from a two-dimensional planar contact to a three-dimensional structure. This vertical extension into the depth dimension increases the contact area without increasing the planar footprint, thereby maintaining contact area despite device scaling.
Solution Approach 2:
The contact structure is nested within recess regions formed between active patterns, utilizing the space between devices. The contact extends into these recesses and may contact underlying insulating layers, effectively nesting the contact structure within the available space to maximize contact area without occupying additional planar area.
2Reliability
If contact area is increased to reduce resistance, then contact structure complexity increases
Solution Approach 1:
The contact structure is segmented into distinct portions: a main contact body and vertical extensions into recess regions. These segments serve different functions - the main body provides primary electrical connection while the extensions increase contact area by utilizing space between active patterns. This segmentation allows the complex three-dimensional structure to be formed through sequential processing steps.
Solution Approach 2:
The contact structure exhibits local quality variations with different geometries in different regions. The main contact body has one geometry while the extensions into recess regions have different geometries optimized for their specific locations. This allows tailored contact characteristics in different areas to optimize electrical performance while managing overall structure complexity.
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
The enhanced contact area and reduced contact resistances lead to improved electrical characteristics and performance of the semiconductor device, specifically by increasing the contact area between the source/drain regions and the contacts, thus enhancing the overall efficiency of the semiconductor device.
Implementation Method 1
A plurality of selective epitaxial growth portions may be grown on upper surfaces of respective ones of the plurality of active patterns
Data Source
AI summary
A semiconductor device can include a plurality of active patterns protruding from a substrate and spaced apart on the substrate by first and second distances. A plurality of selective epitaxial growth portions can be each grown on an upper surface of a respective one of the plurality of active patterns. A source/drain contact can be extending across the plurality of selective epitaxial growth portions to remain above top surfaces of first ones of plurality of active patterns that are spaced apart by the first distance between the first ones of plurality of active patterns and can include an extension that extends toward the substrate to below top surfaces of two of the plurality of active patterns that are spaced apart by the second distance between the two of the plurality of active patterns.