Ultra-Low Power Ni/HfO2/TiOx/TiN Resistive Random Access Memory With Sub-30-nA Reset Current

In this letter, we report ultra-low power (sub-30-nA reset current,
$I_{\mathrm {reset}})$
Ni/HfO
₂
/TiO
_x
/TiN RRAM devices that were fabricated with the rapid thermal oxidation of evaporated titanium. RRAM devices show forming-free, bipolar resistive switching behavior, low-resistive state (LRS) nonlinearity, good data retention, and stability. The resistive switching mechanism is mainly attributed to Schottky barrier modulation induced by
$\text{O}^{2-}$
migration at the Ni/HfO
₂
interface. LRS/high-resistive state current conduction is controlled by Schottky emission/trap-controlled space-charge-limited current. The TiO
_x
film is believed to provide a local high-density current for the device, confirmed by conductive atomic force microscope results.