Investigation of Threshold Voltage Disturbance Caused by Programmed Adjacent Cell in Virtual Source/Drain NAND Flash Memory

2011 ◽  
Vol 50 (4S) ◽  
pp. 04DD08
Author(s):  
Wandong Kim ◽  
Dae Woong Kwon ◽  
Jung Hwan Ji ◽  
Jung Hoon Lee ◽  
Jong-Ho Lee ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Flash Memory ◽  
Adjacent Cell ◽  
Nand Flash ◽  
Virtual Source ◽  
Nand Flash Memory

Investigation of Threshold Voltage Disturbance Caused by Programmed Adjacent Cell in Virtual Source/Drain NAND Flash Memory

2011 ◽  
Vol 50 (4) ◽  
pp. 04DD08 ◽  
Author(s):  
Wandong Kim ◽  
Dae Woong Kwon ◽  
Jung Hwan Ji ◽  
Jung Hoon Lee ◽  
Jong-Ho Lee ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Flash Memory ◽  
Adjacent Cell ◽  
Nand Flash ◽  
Virtual Source ◽  
Nand Flash Memory

Variation of Threshold Voltage and ON-Cell Current Caused by Cell Gate Length Fluctuation in Virtual Source/Drain NAND Flash Memory

2012 ◽  
Vol 51 ◽  
pp. 074301 ◽  
Author(s):  
Wandong Kim ◽  
Yoon Kim ◽  
Se Hwan Park ◽  
Joo Yun Seo ◽  
Do Bin Kim ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Flash Memory ◽  
Gate Length ◽  
Nand Flash ◽  
Virtual Source ◽  
Nand Flash Memory ◽  
Cell Current

Variation of Threshold Voltage and ON-Cell Current Caused by Cell Gate Length Fluctuation in Virtual Source/Drain NAND Flash Memory

2012 ◽  
Vol 51 (7R) ◽  
pp. 074301 ◽  
Author(s):  
Wandong Kim ◽  
Yoon Kim ◽  
Se Hwan Park ◽  
Joo Yun Seo ◽  
Do Bin Kim ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Flash Memory ◽  
Gate Length ◽  
Nand Flash ◽  
Virtual Source ◽  
Nand Flash Memory ◽  
Cell Current

scholarly journals A New Read Scheme for Alleviating Cell-to-Cell Interference in Scaled-Down 3D NAND Flash Memory

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1775
Author(s):  
Jae-Min Sim ◽  
Myounggon Kang ◽  
Yun-Heub Song
Keyword(s):  
Electric Field ◽  
Flash Memory ◽  
Computer Aided Design ◽  
Fundamental Problem ◽  
Adjacent Cell ◽  
Nand Flash ◽  
Nand Flash Memory ◽  
Fundamental Cause ◽  
Tcad Simulation ◽  
Aided Design

In this paper, we investigated the cell-to-cell interference in scaled-down 3D NAND flash memory by using a Technology Computer-Aided Design (TCAD) simulation. The fundamental cause of cell-to-cell interference is that the electric field crowding point is changed by the programmed adjacent cell so that the electric field is not sufficiently directed to the channel surface. Therefore, the channel concentration of the selected cell is changed, leading to a Vth shift. Furthermore, this phenomenon occurs more severely when the selected cell is in an erased state rather than in a programmed state. In addition, it was confirmed that the cell-to-cell interference by the programmed WLn+1 is more severe than that of WLn−1 due to the degradation of the effective mobility effect. To solve this fundamental problem, a new read scheme is proposed. Through TCAD simulation, the cell-to-cell interference was alleviated with a bias having a ΔV of 1.5 V from Vread through an optimization process to have appropriate bias conditions in three ways that are suitable for each pattern. As a result, this scheme narrowed the Vth shift of 67.5% for erased cells and narrowed the Vth shift of 70% for programmed cells. The proposed scheme is one way to solve the cell-to-cell interference that may occur as the cell-to-cell distance decreases for a high stacked 3D NAND structure.

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