Nanostructure Transistor Inner Spacers to Reduce Voids
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Solution Overview
Problem
As semiconductor devices shrink in size, transistors face issues such as short channel effects, increased source/drain electron tunneling, and fabrication challenges with nanostructure transistors like nanowires and gate-all-around devices, leading to performance degradation and yield reduction.
Innovation Solution
The formation of nanostructure transistors includes inner spacers with concave-shaped regions to reduce defects and voids during fabrication, enhancing yield and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transistors are scaled down to smaller technology nodes, then device density and integration are improved, but short channel effects and electron tunneling increase causing performance degradation
Solution Approach 1:
The patent transitions from planar 2D channel structures to three-dimensional nanostructure channels (nanowires, nanosheets, gate-all-around devices) where the gate completely surrounds the channel in multiple dimensions. This dimensional change provides superior electrostatic control over the channel, effectively suppressing short channel effects and reducing electron tunneling even at scaled dimensions, thereby maintaining transistor performance while achieving higher device density.
2Ease of manufacture
If conventional fabrication methods are used for nanostructure transistors, then manufacturing process simplicity is maintained, but defects and voids increase reducing yield
Solution Approach 1:
The patent introduces inner spacers that are formed prior to the main fabrication processes. These pre-formed spacers serve as templates and protective structures during subsequent manufacturing steps, preventing defects and voids from forming in critical areas. The preliminary placement of these spacers ensures proper material deposition and structural integrity throughout the fabrication sequence, significantly improving yield without complicating the overall process.
Solution Approach 2:
The inner spacers act as intermediary structures between the substrate and the final transistor components. These spacers mediate the fabrication process by providing controlled interfaces for material deposition, preventing direct contact that could cause defects, and ensuring uniform formation of channel structures. The intermediary spacers facilitate precise control over critical dimensions and reduce void formation during manufacturing.
Data Source
AI summary
Some implementations described herein provide a nanostructure transistor including inner spacers between a gate structure and a source/drain region. The inner spacers, formed in cavities at end regions of sacrificial nanosheets during fabrication of the nanostructure transistor, include concave-regions that face the source/drain region. Formation techniques include forming the sacrificial nanosheets and inner spacers to include certain geometric and/or dimensional properties, such that a likelihood of defects and/or voids within the inner spacers and/or the gate structure are reduced.