Electrical properties and nanoresistive switching of Ni-HfO2-Si capacitors

Abstract

Ni/HfO2/Si ReRAM devices were extensively characterized. In the pristine state, they show adequate performance with low leakage currents and moderate interfacial state density. Leakage current is dominated by Poole-Frenkel mechanism. Activation energies of conduction processes and soft-optical phonons in the insulator bulk are 80 and 50 meV, respectively. Both are usual values in high-k dielectrics. Devices show unipolar resistive switching behavior, with two well-defined resistance states. They can switch properly at temperatures as low as 77 K. Transitions between both resistance states are electric field and temperature dependent