Self-compliance set switching (SCSS) offers the promise of a selector-less resistive random access memory (RRAM) implementation on flexible substrates, with great application in integrated flexible electronics. SCSS has been realized in RRAM devices with a series oxide layer incorporated into the memory stack. The series oxide acts as an in-built resistor, limiting the increase of the current during set transition. In this study, we show that SCSS can also be achieved in a bipolar RRAM cell without a series oxide layer, i.e., consisting of only a single switching oxide layer. This study reveals that oxygen pileup at the anode interface during the set evolution plays a crucial role in SCSS. The accumulation of oxygen gives rise to the increase of the switching oxide resistance, partially compensating the decrease of the filament resistance, and modulates the conduction barrier at the anode/oxide interface, which self-arrests the increase of the set switching current. Our results show interface engineering as a possible route for enabling SCSS in an RRAM device without the need for a complicated stack structure and careful thickness optimization.
Keywords: hafnium oxide; interface engineering; resistive switching memory; selector-less memory; self-compliance switching.