Bias polarity dependent data retention of resistive random access memory consisting of binary transition metal oxide

Abstract

The authors investigated the data retention properties of NiOy resistors exposed to sputtered particles and found that they depended on the bias polarity used to program the data. Only the data in the high resistance state programmed by applying positive bias to the top electrode were easily damaged. This suggests that the “reset” process can take place when the anodic side of the conductive filaments, which were formed during the “forming” process, is insulated. In addition, the data retention test for thermal stress suggests that the reset process can take place thermally.

I-V measurement of NiO nanoregion during observation by transmission electron microscopy

“…The results presented here support the model where breakdown contributes to the appearance of a conductive filament during the forming process. [20][21][22] Conductive filaments would be generated selectively at weak points against the electric field during the forming process. Therefore, investigations into electric inhomogeneity are important to enable reliable ReRAM devices to be fabricated.…”

Voltage bias induced modification of the transport property of all oxide Pr0.5Ca0.5MnO3/SrTi0.95Nb0.05O3 junctions

“…Generally unipolar switching are seen in binary oxides, 18,19 which form one class of device while the perovskite oxides like PCMO which show bipolar switching behavior 22 form yet another class.…”

“…Thus application of a positive bias to PCMO makes the junction forward bias. In both of them the carrier density can be quite large (~10 18 The migration involves barrier crossing and will happen along paths where the barriers are low.…”

“…Appearance of such a filament has been proposed in the case of unipolar switching in binary oxides. 18,19 To check for appearance of such filaments we have taken cross-sectional TEM of the devices. This is shown in Figure 7.…”

Interpretation of nanoscale conducting paths and their control in nickel oxide (NiO) thin films

“…1͑a͒. It is generally accepted by several authors [4][5][6][7] that the resistance switching materials become conductive by formation of conducting paths such as nanofilaments and/or nanobridges, and become insulating by their disconnection by fuse or rupture effect. The initialization of resistance switching, the so-called electroforming process in NiO thin films is usually performed by applying a dc voltage sweep from 0 to about 3 V with a compliance current of around 1 mA.…”