Searching Optimal Growth Parameters for HfO Applied by Plasma-Enhanced Atomic Layer Deposition Method

The properties of thin HfO2 films grown by plasma-enhanced atomic layer deposition on Si substrates at various temperatures 80,120, and 160°C are studied in this work. For each temperature, the dependences of the growth rate per cycle on the post-plasma pumping time were determined. For the majority of temperatures, saturation of the growth rate per cycle depend of the post-plasma purge time was observed. Accordingly, the optimal times of growth stages were determined for temperatures 80,120, and 160°C. Studies of the chemical composition of the HfO2 film by the XPS method showed that hafnium is bound to oxygen,and increasing of the post-plasma purge time reduces the content of suchimpurities as nitrogen and carbon. The electrophysical properties of HfO2 films have been measured: such asthe capacitance, the dielectric constant and theleakage current density. The values of the built-in charge in HfO2 film were 2.92 and 2.08 × 10-7 C/cm2 for growth temperaturesof 120°C and 160°C, respectively. The dielectric constant for the HfO2 film was 10.8 and 11.8 for temperatures of 120 and 160°C, respectively.