Interface engineering of ALD HfO2-based RRAM with Ar plasma treatment for reliable and uniform switching behaviors

Abstract

The improved resistive switching (RS) characteristics of Pt/HfO2/Ti structured RRAM are demonstrated by engineering interface with argon (Ar) plasma irradiation. The Ar plasma treatment was intentionally carried out on the surface of atomic layer deposited (ALD) HfO2 thin films to modulate the conducting filament size affecting RS behaviors. Compared to ALD HfO2 RRAM without Ar plasma treatment, the Ar plasma treatment on the surface of ALD HfO2 thin film leads to forming-free process, faster switching speed, tighter low resistance state (LRS) and high resistance state (HRS) current distribution, smaller variations of SET voltage and RESET voltage, and enhanced retention/endurance characteristics under HRS. These improvements are believed to be the generation of favorably modulated interface oxide layer between HfO2 and Ti. In addition, current conduction mechanism is dominated by ohmic behavior in LRS while ohmic, space charge limited conduction (SCLC), and trap filled SCLC are observed at HRS with different field regions. The Ar plasma irradiation can be an easy and facile way to achieve the reliable and uniform RRAM characteristics.