HfO2 is considered to be used as a dielectric but if it crystallizes locally its electrical properties becomes unstable. This happens around 700-800 C, which is below where most semiconductor anneals require. Shouldn't this preclude its use?
HfO2, also known as hafnium dioxide, is a chemical compound composed of hafnium and oxygen atoms. It is commonly used in the production of semiconductors and as a high-k dielectric material in electronic devices.
HfO2 can crystallize in three different crystal structures: monoclinic, tetragonal, and cubic. The most stable phase at room temperature is monoclinic, but it can transform into tetragonal or cubic at high temperatures.
The crystallization of HfO2 can be influenced by various factors, including temperature, pressure, and the presence of impurities. The rate of cooling during the crystallization process can also impact the resulting crystal structure.
Crystallized HfO2 has various applications, including as a dielectric in microchips, as a protective coating in optical devices, and as a catalyst in chemical reactions. It is also being studied for potential use in fuel cells and solar cells.
HfO2 is generally considered safe for use in electronic devices and other applications. However, inhalation or ingestion of large amounts of hafnium compounds may cause health issues, so proper handling and disposal are necessary.