Ferroelectric Polarization Aided Low Voltage Operation of 3D NAND Flash Memories

Ilsik Ham,Myounggon Kang,Seung Jae Baik,Youngseok Jeong

doi:10.3390/electronics10010038

Ilsik Ham, Myounggon Kang + Show 2 more

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https://doi.org/10.3390/electronics10010038

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Abstract

In this paper, we proposed a novel structure enabling the low voltage operation of three-dimensional (3D) NAND flash memory. The proposed structure has a ferroelectric thin film just beneath the control gate, where the inserted ferroelectric material is assumed to have two stable polarization states. A voltage for ferroelectric polarization (VPF) that is lower than the program or erase voltage is used to toggle the polarization state of the ferroelectric thin film, whose impact on the channel potential profile is analyzed to optimize operation voltage reduction. The channel potential of select word line (WL), where the natural local self-boosting (NLSB) effect occurs, increases due to the polarization state. Model parameters for the ferroelectric thin film of 8 nm are fixed to 15 µC/cm2 for remanent polarization (Pr), 30 µC/cm2 for saturation polarization (Ps), and 2 MV/cm for coercive field (Ec). Within our simulation conditions, a program voltage (VPGM) reduction from 18 V to 14 V is obtained.

Highlights

The growing demand for data storage devices such as solid-state drives (SSD), mobile phones, and data centers has been supported by high density NAND flash memories
A low voltage NAND flash memory cell is proposed with ferroelectric thin film just beneath the control gate, where ferroelectric polarization gives an auxiliary biasing for the reduction of program or erase voltages
We proposed a novel structure composed of ferroelectric material for the 3D NAND flash memory

Summary

Introduction

The growing demand for data storage devices such as solid-state drives (SSD), mobile phones, and data centers has been supported by high density NAND flash memories. A low voltage NAND flash memory cell is proposed with ferroelectric thin film just beneath the control gate, where ferroelectric polarization gives an auxiliary biasing for the reduction of program or erase voltages. If the ferroelectric thin film is used, program disturb decreases because high channel potential of selected WL reduces the program disturb in the inhibited string.

Results

Conclusion