Integration of a niobium oxide selector on a tantalum oxide memristor by local oxidation using Joule heating

Abstract

Memristive devices are two-terminal electrical switches with electrical resistance that depends on a state variable equivalent to electrical charge. In practice, multiple memristive devices are arranged into a crossbar array to form such components as memory and logic. For reliable operation of the crossbar array, electrical current sneak paths need to be eliminated by combining a highly nonlinear component, known as selector, with a memristive device. This ensures the explicit selection of an intended memristive device without disturbing the states of surrounding devices. However, integrating a selector onto a memristive device at the circuit level is not an appealing option for large scale integration. In this paper, a monolithic structure that contains a memristive device and a self-aligned selector is presented. A niobium oxide (NbO2) selector is built directly on a tantalum oxide (TaOx) memristive device by fist depositing an Nb layer on a TaOx memristive device and then forming NbO2 at the Nb/TaOx interface. Discussion will focus on an experimental and theoretical assessment on the electrothermal behavior of the Nb/TaOx structure that results in NbO2/TaOx selector/memristive devices.