SOI Semiconductor Body Contact Segmentation
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Solution Overview
Problem
In semiconductor devices using SOI substrates, the floating body effect leads to fluctuations in body potential, causing variations in element characteristics and increased parasitic capacitance, which limits the reduction of power consumption and speed performance.
Innovation Solution
A semiconductor device design featuring a first and second transistor formed in the same active region with a body region, where the transistors have a connection portion to the body region and a lead portion that connects the body region, with the lead portions extending perpendicular to the channel direction and gate electrodes extending on these lead portions, reducing gate capacitance by narrowing the lead and connection portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a T-shaped gate electrode is used to isolate the body contact region from source and drain regions, then electrical isolation is achieved, but gate capacitance increases and layout area expands
Solution Approach 1:
The gate electrode is segmented into two distinct parts: a first gate electrode for the transistor channel and a second gate electrode for isolating the body contact region. This segmentation allows each gate portion to be optimized independently, reducing the total overlapping area between gate and body contact while maintaining electrical isolation functionality.
Solution Approach 2:
A second gate electrode is introduced as an intermediary structure between the body contact region and the source/drain regions. This intermediate gate structure provides the necessary electrical isolation without requiring the body contact region to directly overlap with the main gate electrode, thereby reducing parasitic capacitance.
2Reliability
If the gate electrode extends to isolate the body contact region, then electrical isolation is achieved, but the layout area increases
Solution Approach 1:
The gate structure is divided into separate segments with the second gate electrode positioned specifically for isolation purposes. This segmentation allows the isolation function to be achieved without extending the main gate electrode unnecessarily, optimizing the layout area while maintaining electrical isolation.
Solution Approach 2:
The isolation function is achieved by utilizing the gate electrode structure in a different spatial arrangement - the second gate electrode is positioned to overlap with the body contact region in plan view but is electrically isolated, effectively using vertical stacking and lateral positioning to achieve isolation without expanding the overall layout footprint.
Data Source
AI summary
An active region includes a body region in which first and second transistors are formed, a connection portion to which a potential of the body region is connected, and a lead portion that connects the body region and the connection portion. Source regions or drain regions of the first and second transistors formed in the body region are provided in a common region. Each of the lead portions extends from a corresponding channel region such that the lead portions are isolated from each other, and a gate electrode extends thereon. A width of the lead portion is narrower than a distance between corresponding ones of contact portions of the source regions and the drain regions of the first and second transistors. A width of the connection portion is equal to or narrower than a gate width of the gate electrode extending on the lead portion.