Low-frequency deffusion noise in resistive-switching memories based on metal-oxide polymer structure.

Low-frequency noise is studied in resistive-switching memories based on metal–oxide polymer diodes. The noise spectral power follows a $hbox{1}/f^{gamma}$ behavior, with $gamma = hbox{1}$ in the ohmic region and with $gamma = hbox{3/2}$ at high bias beyond the ohmic region. The exponent $gamma = hbox{3/2}$ is explained as noise caused by Brownian motion or diffusion of defects which induce fluctuations in diode current. The figure of merit to classify $hbox{1}/f$ noise in thin films has an estimated value of $hbox{10}^{-21} hbox{cm}^{2}/Omega$, which is typical for metals or doped semiconductors. This value in combination with the low diode current indicates that the $hbox{1}/f$ noise is generated in the narrow localized regions in the polymer between the contacts. The analysis unambiguously shows that the current in bistable nonvolatile memories is filamentary