Synthesis and Study of Al:HfO₂ Thin Films for Memristors. Structural and Properties

Comprehensive studies of thin films of hafnia doped by low concentrations of aluminum were carried out. Concentration of aluminum varies from 0 to 3.87 at.% by metal. The main attention is paid to the development of the reactive magnetron sputtering method, which ensures precise stoichiometry control and provides uniform distribution of aluminum dopant through the film volume. The proposed approach is based on the reactive magnetron sputtering Hf02 and Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> by controlling the sputtering rate. Fabricated samples of thin films were examined using atomic force microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction and ultraviolet-visible spectroscopy. The changes in the film morphology, band gap width and cell parameters of the active layer material depending on the dopant fraction are determined. Developed method make it possible to synthesize a solid solution thin films of Al doped Hf02 with a defined concentration of oxygen vacancies, key elements of the resistive switching mechanism.