Origin of multistate resistive switching in Ti/manganite/Si$O_x$/Si heterostructures

TL;DR

This paper investigates the multistate resistive switching mechanisms in Ti/manganite/SiOx/Si heterostructures, revealing the roles of different microscopic regions and the importance of the SiOx layer in stabilizing intermediate resistance states.

Contribution

It introduces a detailed electrical characterization of multilevel resistive states in Ti/manganite/SiOx/Si devices, highlighting the role of the SiOx layer and multiple active oxides in resistive switching.

Findings

Intermediate resistance state unveiled using current stimulus

Three microscopic regions contribute to transport properties

SiOx layer stabilizes the intermediate resistance level

Abstract

We report on the growth and characterization of Ti/$La_{1/3}$$Ca_{2/3}$Mn$O_3$/Si$O_x$/n-Si memristive devices. We demonstrate that using current as electrical stimulus unveils an intermediate resistance state, in addition to the usual high and low resistance states that are observed in standard voltage controlled experiments. Based on thorough electrical characterization (impedance spectroscopy, current-voltage curves analysis), we disclose the contribution of three different microscopic regions of the device to the transport properties: an ohmic incomplete metallic filament, a thin manganite layer below the filament tip exhibiting Poole-Frenkel like conduction, and the SiOx layer with an electrical response well characterized by a Child-Langmuir law. Our results suggest that the existence of the SiOx layer plays a key role in the stabilization of the intermediate resistance level, indicating that the combination of two or more active RS oxides adds functionalities in relation to single-oxide devices. We understand that these multilevel devices are interesting and promising as their fabrication procedure is rather simple and they are fully compatible with standard Si-based electronics.