Semiconductor Storage Device Floating Gate Insulator Design
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Solution Overview
Problem
Current semiconductor storage devices face challenges in improving electrical characteristics, particularly in readout and writing characteristics, due to the influence of voltage applied to word lines on channels not covered by floating gate electrodes, leading to increased device size and decreased performance.
Innovation Solution
The introduction of second and third insulators between word lines and floating gate electrodes, which are strategically positioned to increase the distance between word lines and uncovered channel regions, thereby reducing the voltage influence and enhancing electrical characteristics without increasing device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between word lines and uncovered channel regions is increased to reduce voltage influence, then electrical characteristics improve, but device size increases
Solution Approach 1:
An insulator is introduced as an intermediary element between the word line and the uncovered channel region. This insulator mediates the electric field interaction, reducing the voltage influence from the word line on the channel while maintaining a compact device structure. The insulator acts as a buffer that allows electrical isolation without requiring increased physical separation distance.
2Volume of moving object
If the floating gate electrode size is reduced to decrease device size, then manufacturing precision requirements increase, but electrical characteristics deteriorate due to increased voltage influence on channels
Solution Approach 1:
The insulator serves as a protective intermediary that shields the channel from unwanted voltage influence. This allows the floating gate electrode to be reduced in size without compromising electrical characteristics, as the insulator compensates for the reduced shielding effect that would normally be provided by a larger floating gate structure.
3Reliability
If insulators are added between word lines and floating gate electrodes to reduce voltage influence, then electrical characteristics improve, but device complexity increases
Solution Approach 1:
The insulator is segmented to be positioned only in specific locations where it is most effective - between the word line and uncovered channel regions. This selective placement provides the necessary electrical isolation to improve characteristics while minimizing the addition of structural complexity compared to a comprehensive insulator layer throughout the entire device.
Data Source
AI summary
According to one embodiment, a semiconductor storage device includes a first interconnection, a second interconnection, a first channel part, a second channel part, a first charge storage part, a second charge storage part, a first insulator, a second insulator, and a third insulator. The first insulator includes a portion between at least a portion of the first charge storage part and at least a portion of the second charge storage part, and extends in a first direction. The second insulator is between the first insulator and the first interconnection, and extends in the first direction at a position arranged with respect to the first charge storage part in the first direction. The third insulator is between the second interconnection and the first insulator, and extends in the first direction at a position arranged with respect to the second charge storage part in the first direction.