Modulation of the Electrical Characteristics of HfOx/TiN RRAM Devices through the Top Electrode Metal

Abstract

The effect of the top electrode on switching characteristics of a HfOx/TiN structure was investigated. From the electrical conduction analysis, the conduction mechanism between Pt and Ti was found to be quite different. A potential barrier formed in the Pt/HfOx interface showing the Fowler-Nordheim tunneling at high bias. However, it was not observed in the Ti/HfOx structure. Reactive metal Ti interacted with the underlying HfOx film leading to destruction of the barrier height. As such, the device lost the ability to operate at the mu A compliance current range. Pt/HfOx demonstrated the merit of a large resistance ratio and a low operation current (Ireset = 20 mu A). However, Ti/HfOx exhibited better voltage dispersion at the low resistance state (0.5V dispersion). The electrode plays a dominant role in determining the electrical characteristics of a resistive random access memory (RRAM) device. Therefore, choosing an adequate electrode for RRAM is an important consideration.