Introduction to HfO2 Thin Films

Hafnium dioxide (HfO2) is a high-k dielectric material with a wide bandgap and high thermal stability, making it an attractive material for thin film applications. HfO2 thin films have been extensively studied for their use in ferroelectric and dielectric applications.

In ferroelectric applications, HfO2 thin films exhibit a high remnant polarization and a low coercive field, making them ideal for non-volatile memory applications. The ferroelectricity properties of HfO2 are still under investigation, but recent studies have shown promising results.

Compared to lead zirconate titanate (PZT), which is a commonly used ferroelectric material, HfO2 has a higher breakdown strength and a lower leakage current, making it more suitable for high-power and high-frequency applications.

Crystal Structure of HfO2

The crystal structure of HfO2 is monoclinic, with a lattice parameter of approximately 0.504 nm. It has a high degree of oxygen vacancy defects, which can be controlled by doping with other elements.

Common Substates for HfO2 Thin Films

Some typical substrates with a good lattice match used for epitaxial growth of HfO2 include Si(001), Si(111), and YSZ(111). Other non-matching substrates such as sapphire, glass, and quartz can also be used with appropriate buffer layers.

Other Ferroelectric Thin Film Materials

• Pb(Zr,Ti)O3
• BaTiO3
• KNbO3
• BiFeO3
• LaAlO3

Other Dielectric Thin Film Materials

• Al2O3
• HfSiO4
• TiO2
• SiO2
• ZrO2