HfO 2 films were produced from Hf[N(CH 3 )(C 2 H 5 )] 4 and H 2 O, on borosilicate glass, indium-tin-oxide (ITO), and Si(100) substrates, in the temperature range 150±325 C, using atomic layer deposition (ALD). In the temperature range 200±250 C, the growth rate of the HfO 2 films was 0.09 nm per cycle, but increased with both increasing and decreasing temperatures. The self-limiting adsorption of Hf[N(CH 3 )(C 2 H 5 )] 4 at 250 C was verified. The films were stoichiometric dioxides with an O/Hf ratio of 2.0 ± 0.1. The concentrations of residual carbon, nitrogen, and hydrogen, determined using ion beam analysis, were 0.3±0.6 at.-%, 0.1±0.2 at.-%, and 2±3 at.-%, respectively. The films crystallized at growth temperatures exceeding 150±175 C, and consisted mainly of the monoclinic HfO 2 phase. The refractive index of the films varied between 2.08 and 2.10. The effective permittivities of the HfO 2 films grown in the temperature range 200±300 C varied between 11 and 14.