Semiconductor Control Gate Segmentation for Contact Reduction
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Solution Overview
Problem
In semiconductor devices with nonvolatile memory, the technique of cutting off both the word gate and control gate electrodes to prevent erroneous writing increases the number of contacts required, hindering the reduction of device size.
Innovation Solution
A semiconductor device design featuring first and second word gates with lateral control gates connected by separate connection portions, including disconnection portions between these connections, allows for reduced contact numbers while preventing erroneous writing by ensuring only selected control gates are disconnected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both the word gate and control gate electrodes are cut off in the same place to prevent erroneous writing, then erroneous writing is suppressed, but the number of contacts connected to the word gate must be increased
Solution Approach 1:
The control gate electrode is segmented into multiple portions with disconnection portions between them, allowing selective disconnection of control gates while maintaining word gate continuity. This segmentation enables precise voltage application to selected memory cells without affecting adjacent cells, suppressing erroneous writing while avoiding the need for additional word gate contacts.
Solution Approach 2:
The disconnection portions are extracted specifically from the control gate electrode structure, separating the control gate into distinct segments. This extraction allows the control gate to be disconnected at specific locations without disconnecting the word gate, thereby preventing erroneous writing while maintaining the word gate's electrical continuity and avoiding increased contact requirements.
2Ease of manufacture
If the control electrodes facing each other are connected to the same contact with the connection layer interposed therebetween, then the manufacturing process is simplified, but voltage is also applied to the control electrode which is not selected, causing erroneous writing
Solution Approach 1:
The connection layer is segmented into separate connection portions, each connected to specific control gate portions. The disconnection portions in the control gate electrode create electrical isolation between adjacent control gates, ensuring that voltage applied to one control gate does not affect adjacent control gates, thereby preventing erroneous writing while maintaining manufacturing simplicity.
Solution Approach 2:
Different regions of the control gate electrode have different electrical properties - connected regions allow voltage application while disconnection portions provide electrical isolation. This local differentiation ensures that voltage is applied only to selected control gates and not to adjacent control gates, preventing erroneous writing while maintaining a relatively simple manufacturing process.
Data Source
AI summary
A first connection portion and a second connection portion connect a first control gate to a second control gate, and are separated from each other. The first control gate includes a first disconnection portion between the first connection portion and a source diffusion layer closest to the first connection portion. The second control gate includes a second disconnection portion between the second connection portion and the source diffusion layer closest to the second connection portion. A first word gate and a second word gate are not disconnected in portions overlapping the first disconnection portion and the second disconnection portion.