Stabilized resistive switching behaviors of a Pt/TaOx/TiN RRAM under different oxygen contents

Abstract

We demonstrate enhanced resistive switching (RS) stability, as measured by distribution, power consumption, and memory window, using different oxygen contents in a Ta oxide (TaOx) layer with a Pt top electrode and a TiN bottom electrode. The stability of the Pt/TaOx/TiN RRAM device increases as the oxygen contents of the TaOx layer increase. When oxygen is introduced during TaOx deposition, conventional bipolar RS (BRS) switches to self-compliant BRS, and distribution is improved within 200 repeated RS cycles. We investigate the conduction mechanisms for both a low resistance state (LRS) and a high resistance state (HRS). Ohmic conduction in the LRS and for the low bias region in the HRS corresponds to the conductive filament (CF) theory, while Poole-Frenkel (PF) conduction in the high bias region of HRS is the dominant conduction mechanism. A possible RS mechanism with oxygen ion drift is discussed.