Non-destructive read ferroelectric multi-logic state memory cell and write/read/erase operation method for storing data based on domain wall density

Abstract

The purpose of the present invention is to provide a ferroelectric multi-logic state memory cell and its read / write / erase operation method, which uses oxide electrodes to clamp ferroelectric epitaxial ferroelectric thin films, and metal electrodes pass through the oxide electrodes and the epitaxial ferroelectric film at the same time. Electric film contact, by controlling the write voltage pulse to control the nucleation of the electric domain inside the ferroelectric film and the movement of the ferroelectric domain wall, so that the formed ferroelectric domain wall moves around from the contact position between the metal electrode and the ferroelectric film; through Change the direction of the voltage pulse to flip the electric domain, generate a new domain wall and make it move outward; control the moving distance of the domain wall by controlling the voltage pulse, so that the domain walls will not affect each other. This structural design can control the position of the domain nucleation in the ferroelectric film, and can control the movement position of the ferroelectric domain wall through the action time of the pulse voltage, which can effectively improve the control of the position of the ferroelectric domain wall and the storage of data in the memory cell. stability, and promote the application of multi-logic state ferroelectric domain wall memory devices.

Description

technical field [0001] The invention relates to the field of information technology storage, and in particular provides a non-destructive read ferroelectric multi-logic state storage unit and a writing / reading / erasing operation method for storing data based on domain wall density. Background technique [0002] Ferroelectric memory has the advantages of wide operating temperature range, fast read and write speed, anti-fatigue, low power consumption, and radiation resistance, and has attracted great attention in the military and civilian fields. Ferroelectric memory stores data based on the orientation of the electric domains of the ferroelectric film. Under the action of an external electric field or force field, the conversion of binary "1" and "0" can be realized through the flipping of the electric domains. However, under the trend of device miniaturization, when the device memory cell size is less than 130nm, the current readout circuit is basically unable to recognize th...

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Problems solved by technology

However, at present, ferroelectric memory still faces severe problems in multi-logic ferroelectric storage, especially the controllability of ferroelectric domain walls needs to be improved.

Taking the invention content described in the US invention patent (US12839411) as an example, it is aimed at 5nm-25nm thick BiFeO 3 , BaTiO 3 The control of ferroelectric domain walls in the thin film has been designed, but in the actual operation process, because the existence of ferroelectric domain walls depends on the internal defects of the film and the writing method of domain walls, the design structure for the formation of ferroelectric domain walls The position is not clear. Although it is theoretically possible to achieve multi-logic state storage, the formation position of the ferroelectric domain wall and the controllability of the conductivity are not clear, especially by controlling the magnitude of the voltage to achieve the ferroelectric domain wall. Formation, making it difficult to control the position, configuration and thickness of domain walls in ferroelectric thin films

It is difficult to achieve the thickness of the ferroelectric domain wall under the electric field of non-parallel electrodes by the size of the voltage value. In this design, the thickness of the ferroelectric domain wall will be significantly larger than that of the ordinary domain wall, which will directly restrict the conductivity of the ferroelectric domain wall and the ferroelectric domain wall. The number of domain walls in the film limits the multi-logic state storage performance of ferroelectric domain wall storage

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