GAA Nanowire Source-Drain Isolation for Tighter Transistor Spacing
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Solution Overview
Problem
The challenge of maintaining mobility improvement and short channel control in microelectronic devices as device dimensions scale below the 10 nanometer node, particularly in multi-gate and nanowire transistors, is compounded by the trade-off between feature patterned dimension and spacing, leading to issues like electrical shorts between adjacent transistors.
Innovation Solution
Implementing a physical barrier composed of low-k dielectrics to separate adjacent transistors in gate-all-around integrated circuit structures, using self-aligned gate endcap (SAGE) architectures to prevent epitaxial shorts and enable more aggressive diffusion-to-diffusion spacing, while maintaining high layout density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If device dimensions are scaled down to increase density, then capacity increases, but electrical shorts between adjacent transistors occur
Solution Approach 1:
A dielectric material is introduced as an intermediary substance between adjacent epitaxial semiconductor structures to prevent electrical shorts. The dielectric material fills the trench and provides electrical isolation, enabling devices to be placed closer together without compromising reliability.
Solution Approach 2:
The space between adjacent devices is segmented into distinct regions by forming a trench and filling it with dielectric material. This segmentation creates clear electrical boundaries between devices, allowing for higher density while maintaining isolation.
2Quantity of substance
If lithographic spacing is reduced to increase layout density, then device density increases, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The self-aligned fabrication process allows previously formed structures to serve as alignment references for subsequent steps. The gate structure and earlier-formed features automatically define the positioning of adjacent devices, eliminating the need for additional lithographic alignment and maintaining precision at reduced spacings.
Solution Approach 2:
Trenches for dielectric insertion are formed at predetermined locations during earlier fabrication steps, before final device formation. This preliminary action establishes the isolation structure in advance, ensuring proper spacing and alignment is maintained throughout subsequent processing.
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 effectively prevents electrical shorts and allows for more aggressive scaling of transistor layouts, enhancing performance and functionality in integrated circuits.
Implementation Method 1
a first epitaxial source or drain structure and a second epitaxial source or drain structure are physically separated from one another by an intervening dielectric structure
Implementation Method 2
embodiments are directed to lateral confinement of epitaxial growth in non-planar transistor
Data Source
AI summary
Gate-all-around integrated circuit structures having epitaxial source or drain region lateral isolation are described. For example, an integrated circuit structure includes a first vertical arrangement of nanowires and a second vertical arrangement of nanowires. A gate stack is over the first and second vertical arrangements of nanowires. First epitaxial source or drain structures are at ends of the first vertical arrangement of nanowires. Second epitaxial source or drain structures are at ends of the second vertical arrangement of nanowires. An intervening dielectric structure is between neighboring ones of the first epitaxial source or drain structures and the second epitaxial source or drain structures. The intervening dielectric structure has a top surface co-planar with a top surface of the gate structure.