Interface Modulated Pd/Nb-SrTiO₃ Resistive Switching Via Hydrogen Intercalation

Resistive random-access memory (RRAM) or memristor devices are one of the most promising technologies to achieve low-cost, high endurance, low power consumption, and CMOS compatible neuromorphic hardware to address “memory wall” problem. Strontium titanate SrTiO₃ (STO) is an ideal candidate, due to large bandgap, to be used as an insulator in the simple metal/insulator/metal (MIM) architecture for resistive switching. By modulating the Schottky barrier height through applied bias, it is possible to tune the resistance states of MIM devices. Thus, interface kinetics play a crucial role in determining the resistive switching mechanism for memristor devices consisting of a Schottky junction. In this work, we examine the interfacial properties of Pd/Nb-STO resistive devices with and without hydrogen intercalation. Hydrogen molecules get adsorbed, dissociate to hydrogen atoms, and split to protons at Pd/Nb-STO interface. The I-V hysteresis characteristics reveal that the intercalated protons reduce the barrier height by 100 mV compared to sample without hydrogen annealing and decrease the resistance under reverse bias condition. The decrease in the resistance (under reverse bias condition) for annealed sample is attributed to an decrease in built-in potential (from C-V measurements). These devices showed high retention time, large off/on ratio, and fast switching characteristics.