Five- ∼ 5.9-nm-thick pure HfO2 and Hf-silicate films having different compositions (Hf31Si4O65, Hf 20Si14O66 and Hf9Si 24O66) were grown on Si (100) substrates by using atomic layer deposition, and their electrical properties were examined in relation to the post-deposition annealing temperature by using capacitance-voltage measurements. In contrast to other samples, only the Hf20Si 14O66 film exhibited a phase separation phenomenon in the direction of the film normal with increasing annealing temperature, which was confirmed by cross-sectional high-resolution transmission electron microscopy (HRTEM). In the case of the Hf-rich (Hf31Si4O 65) and Si-rich (Hf9Si25O66) samples, the flatband voltage was negatively shifted with increasing annealing temperature, mainly due to the growth of the interfacial oxide. However, the flatband voltage of the Hf20Si14O66 film was positively shifted as the annealing temperature was increased up to 800 °C, probably due to the spinodal decomposition process, and returned back to its original value at 900 °C due to a mechanism similar to that observed in the other samples.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)