Structure of Hf0.9La0.1O2 Ferroelectric Films Obtained by the Atomic Layer Deposition

Thin films of La-doped hafnium oxide synthesized by plasma-enhanced atomic layer deposition with subsequent rapid annealing have been studied. It has been found that the films under study have an orthorhombic noncentrosymmetric structure with the space group Pmn21. It has been shown that these films have ferroelectric properties. The ratio of atomic concentrations of elements in a film has been determined. It has been found that the film consists of the mixture of the HfO2 and La2O3 phases. It has been shown that argon ion etching results in the generation of oxygen vacancies with a concentration of about 1 at % in the surface region of the films. Vacancies are formed primarily through the knock-out of oxygen atoms to interstitial positions with the formation of a Frenkel pair.