In-situElectron Microscopy of Cu Movement in MoO_x/Al₂O₃Bilayer CBRAM during Cyclic Switching

Abstract

In-situ TEM (transmission electron microscopy) was applied to Cu/MoOx/Al2O3 bilayer CBRAM and the change of the Cu microstructure were observed during cyclic Set/Reset switching. In the Set process giving the low resistance state (LRS), a dark contrast appeared in Al2O3 layer, and in the Reset process giving the high resistance state (HRS), it almost disappeared. This result means that the resistance changed by formation and rupture of the conducting filament. In our MoOx/Al2O3 CBRAMs, cyclic Set/Reset operations were achieved with the real-time TEM observations. During the cycles, device degradation, i.e., gradual decrease in the resistance in the cyclic operation was observed in the both HRS and LRS. We confirmed that the contrast of the Cu layer and the Al2O3 layer had changed while the device degraded.

Filamentary switching of ReRAM investigated by in-situ TEM

“…The used sample structure was Cu (30) /MoO x(20) /Al 2 O 3 (5) formed on a TiN/Si substrate and was processed via the FIB technique. [82][83][84] The number the parentheses indicates the film thickness in nm. A typical Set curve is shown in Fig.…”

Initialization process of Cu-based WO x conductive bridge RAM investigated via in situ transmission electron microscopy

“…Among these techniques, in situ TEM is an effective method that can be used to observe the internal state of CBRAM during switching cycles. 10,27) Filament formation/rupture along with resistive switching, 17,22,28,29) filament morphology and dynamics, 20) and device degradation processes 30,31) have been experimentally investigated.…”