Forming-free memristors based on hafnium oxide processed in electron cyclotron resonance hydrogen plasma

It is shown that the treatment of stoichiometric HfO$_2$, which is synthesized by atomic layer deposition, in electron cyclotron resonance hydrogen plasma leads to a significant depletion of the film in oxygen and the formation of nonstoichiometric HfO$_x$ ($x<2$). The longer the treatment time, the higher the degree of oxygen depletion. The charge transfer in the films under study occurs by phonon-assisted tunneling between oxygen vacancies serving as traps. It has been found that the ${{p}^{{ + + }}}$-Si/HfO$_x$/Ni structures, where the oxide layer is treated in the electron cyclotron resonance hydrogen plasma, have memristor properties: they are reversibly switched between high and low resistance states. The fabricated memristor structures are forming-free.