Change Character of Conductivity in Metal–Insulator–Metal Thin Films

Abstract

Herein, the possibility of changing the conductivity of thin‐film systems consisting of two metals separated by an insulator (metal–insulator–metal, MIM) is shown. The electrophysical properties are studied in three systems: Fe/MgO/Ni, Fe/MgO/Co, and Fe/MgO/Fe + C (Fe doped with carbon). The resulting inhomogeneity in thickness of the dielectric layer over the junction area promotes the appearance of local conduction regions. This makes it possible to change the type of conductivity from tunneling to semiconducting. As a result, a region with negative differential resistance is observed in I–V characteristics of MIM systems. The processes of electromigration during the alloying of one of the metal layers are considered. Presence of such processes is confirmed by the results of dynamic and static measurements of conductivity and corresponding assessments. Exposure of the sample in laboratory atmosphere at room temperature for several tens of days provides asymmetrical I–V characteristics. This indicates the rectifying properties of the contact—characteristic of the conductivity of the Schottky diode. The use of MIM systems with the described properties is considered promising for application in modern electronic devices as basic elements and memory cells.