Having a high dielectric constant and potential to form device-grade interface to silicon, hafnium oxide (Hf0₂) is considered as the promising potential substitute for Si0₂ as the gate dielectric in future technology nodes. However, many properties of this material are still not clear and need to be studied. This thesis studied the material characteristics of the HfO₂ film, in order to improve the quality of the dielectric film. _{2 2 2}...[ Read more ]

Having a high dielectric constant and potential to form device-grade interface to silicon, hafnium oxide (Hf0₂) is considered as the promising potential substitute for Si0₂ as the gate dielectric in future technology nodes. However, many properties of this material are still not clear and need to be studied. This thesis studied the material characteristics of the HfO₂ film, in order to improve the quality of the dielectric film.

First, the direct sputtering of HfO₂ film on silicon was studied. Different Post Deposition Annealing (PDA) conditions were applied to the as-deposited film. Conventional MOS capacitors were used to extract the electrical characteristics of the Hf0₂ film. Effects of PDA on the chemical and physical characteristics of the sputtered HfO₂ film were studied using X-ray Photoelectron Spectroscopy (XPS). The results allowed an accurate computation of a correlation among the PDA conditions.

Second, the PDA effects on the interface and oxide charges of the fabricated MOS capacitors were investigated systematically. The stress-induced charge trapping and de-trapping characteristics were analyzed. The results allowed an optimization of the PDA conditions so that Hf0₂ film with the least interface charge density could be fabricated.

Finally, the current conduction and reliability of the HfO₂ film were studied. The results demonstrated that direct tunneling, trap-assistant-tunneling and FN tunneling were dominant at different voltage regions. Together with the study of area and stress voltage effects on the Time Dependent Dielectric Breakdown (TDDB), the ten-year lifetime operation voltage was computed.