Effects of bottom electrode on resistive switching of silver programmable metallization cells with Gd_xO_y/Al_xO_y 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 (Gd_xO_y/Al_xO_y) 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 Gd_xO_y/Al_xO_y 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.