Structure of Hf$_{0.9}$La$_{0.1}$O$_2$ 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 $Pmn2_1$. 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 HfO$_2$ and La$_2$O$_3$ 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.