Unipolar resistive switching behavior of high-k ternary rare-earth oxide LaHoO3 thin films for non-volatile memory applications

Abstract

ABSTRACTRare-earth oxides have attracted considerable research interest in resistive random access memories (ReRAMs) due to their compatibility with complementary metal-oxide semiconductor (CMOS) process. To this end we report unipolar resistive switching in a novel ternary rare-earth oxide LaHoO3 (LHO) to accelerate progress and to support advances in this emerging densely scalable research architecture. Amorphous thin films of LHO were fabricated on Pt/TiO2/SiO2/Si substrate by pulsed laser deposition, followed by sputter deposition of platinum top electrode through shadow mask in order to elucidate the resistive switching behavior of the resulting Pt/LHO/Pt metal-insulator-metal (MIM) device structure. Stable unipolar resistive switching characteristics with interesting switching parameters like, high resistance ratio of about 105 between high resistance state (HRS) and low resistance state (LRS), non-overlapping switching voltages with narrow dispersion, and excellent retention and endurance features were observed in Pt/LHO/Pt device structure. The observed resistive switching in LHO was explained by the formation/rupture of conductive filaments formed out of oxygen vacancies and metallic Ho atom. From the current-voltage characteristics of Pt/LHO/Pt structure, the conduction mechanism in LRS and HRS was found to be dominated by Ohm’s law and Poole-Frenkel emission, respectively.