Effects of bottom electrode on resistive switching of silver programmable metallization cells with GdxOy/AlxOy solid electrolytes

This study investigated the effects of the bottom electrode (BE) on the resistive switching (RS) of silver programmable metallization cells (Ag-PMCs) with gadolinium oxide and aluminum oxide (GdxOy/AlxOy) solid electrolytes (SEs). The RS mechanisms of memories with different bottom electrodes were proposed based on the temperature dependence of the resistance at low resistance state (LRS) and current-voltage (I-V) fitting at high resistance state (HRS). The Schottky emission was dominant in the resistive switching of the memory with an iridium bottom electrode (Ir-BE), whereas in the memories with n+-Si and nickel (Ni) bottom electrodes, silver and both silver and nickel ions dominated the resistive switching, respectively. Additionally, the Ag-PMC with Ni-BE had a high resistance ratio of more than 107 as a result of the extremely low resistance of roughly 50 Ω at LRS. The Ag-PMCs with GdxOy/AlxOy SEs and Ni-BE exhibited a retention behavior of more than 104 s and an endurance of more than 500 cycles with a resistance ratio of at least four orders of magnitude, which is promising for future high-density nonvolatile memory applications.