Enhanced resistive switching characteristics of HfOx insulator fabricated by atomic layer deposition and La(NO3)3·6H2O solution as catalytic oxidant

Abstract

Nanocrystalline HfOx films were synthesized by an atomic layer deposition method using Hf[N(CH3)C2H5]4 as the metal precursor and La(NO3)3·6H2O solution as the oxidant. La(NO3)3·6H2O solution played the role of both oxidant and catalyst, catalytic oxidant, where the La element in the deposited HfOx films was under the detection limit. The introduction of La(NO3)3·6H2O solution instead of H2O effectively altered the surface roughness, crystalline status, and resistive switching properties of HfOx films. Although the crystalline structures of both HfOx films made with La(NO3)3·6H2O solution and H2O were monoclinic, the surface roughness of the HfOx film grown by using the La(NO3)3·6H2O solution oxidant is smoother than that using H2O. Moreover, resistive switching characteristics of the HfOx insulator deposited with the La(NO3)3·6H2O solution oxidant enhanced not only uniformity of switching parameters but also endurance.