Semiconductor Memory Device Guard Ring Noise Suppression
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Solution Overview
Problem
There is an increasing demand for the miniaturization of both the cell and peripheral regions in semiconductor memory devices, such as NAND flash memory, while maintaining the stability and efficiency of memory cell transistors and preventing noise and latch-up.
Innovation Solution
The semiconductor memory device incorporates a specific structure with varying insulating film thicknesses and electrode configurations across different regions, including a guard ring to capture minority carriers and stabilize the substrate potential, along with transistors of different breakdown voltages for the row decoder and sense amplifier, to enhance breakdown voltage and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the cell region and peripheral region are miniaturized to meet increasing demand, then device size is reduced, but noise and latch-up risks increase
Solution Approach 1:
The patent applies different insulating film thicknesses to different regions: the cell region uses a first insulating film with a specific thickness, while the peripheral region uses a second insulating film with a greater thickness. This local differentiation allows miniaturization of the overall device while providing enhanced noise suppression and latch-up prevention in the peripheral region through the thicker insulating film, thus resolving the contradiction between device size reduction and harmful factor suppression.
2Object-affected harmful factors
If insulating film thickness is increased to suppress noise and prevent latch-up, then noise and latch-up are reduced, but device area increases
Solution Approach 1:
The patent implements a local quality approach by configuring the first insulating film in the cell region with a specific thickness optimized for cell operation, and the second insulating film in the peripheral region with a greater thickness for noise suppression and latch-up prevention. This regional differentiation ensures that the thicker insulating film is only used where necessary for harmful factor suppression, minimizing the overall device area increase while achieving the desired noise and latch-up reduction.
3Ease of manufacture
If uniform insulating film thickness is used across all regions, then manufacturing is simplified, but peripheral region stability deteriorates
Solution Approach 1:
The patent employs local quality by specifying different insulating film thicknesses for different functional regions: the first insulating film in the cell region and the second insulating film with greater thickness in the peripheral region. This approach maintains manufacturing simplicity through a systematic two-region configuration while significantly improving peripheral region stability and preventing latch-up, thus resolving the contradiction between manufacturing ease and reliability.
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 configuration allows for efficient miniaturization of the memory device, stabilizes the operation of cell transistors, and reduces noise by effectively capturing electrons and suppressing substrate potential variations, thereby improving the overall performance and reliability of the semiconductor memory device.
Implementation Method 1
a guard ring to capture minority carriers and stabilize the substrate potential
Data Source
AI summary
According to one embodiment, a semiconductor memory device includes a semiconductor substrate, a cell transistor, an extraction section, a guard ring, a first transistor, and a second transistor. The semiconductor substrate includes first, second, third, and fourth regions. The fourth region includes first and second portions. The cell transistor is provided on the first region and includes a first insulating film, a charge storage film, and a first electrode. The extraction section is provided on the second region and includes a second insulating film, and an extension electrode. The guard ring is provided on the third region and includes a third insulating. The first transistor is provided on the first portion and includes a fourth insulating, and a second electrode. The second transistor is provided on the second portion and includes a fifth insulating film, and a third electrode.