Flicker Noise Behavior in Resistive Memory Devices With Double-Layered Transition Metal Oxide

Characteristics of flicker (or
$\hbox{1}/f$
) noise have been investigated in resistive-switching random access memory (RRAM) devices with
$\hbox{TiN/Ti/TiO}_{x}/\hbox{HfO}_{x}/\hbox{TiN}$
double-layered (DL) metal oxide structure. In DL-RRAMs, no significant difference is found in the normalized current noise power spectral densities of the high- and low-resistance states, unlike RRAMs with the
$\hbox{TiN/Ti/TiO}_{x}/ \hbox{TiN}$
SL structure. Based on comparative analysis, we demonstrate that the dominant
$\hbox{1}/f$
noise source of DL-RRAM is located near the
$\hbox{TiO}_{x}/\hbox{HfO}_{x}$
and
$\hbox{HfO}_{x}/\hbox{TiN}$
interfaces, and the origin of
$ \hbox{1}/f$
noise is modeled to be the mobility fluctuation. A unique measurement method, which completely breaks down the
$\hbox{HfO}_{x}$
layer only, was employed for a systematic analysis of RRAMs with three different structures.