Hafnium oxide
Properties
Chemical formula: HfO₂
Name: Hafnium(IV) oxide / hafnium oxide
CAS No.: 12055-23-1
Molar mass: 210.49 g/mol
Density: 9.68 g/cm³
Melting point: approx. 2758 °C
Boiling point: approx. 5400 °C
Color: white
Form: fine powder or dense sintered body
Dielectric constant: approx. 25
Band gap: approx. 5.3-5.7 eV
Refractive index: approx. 2.1
Hafnium oxide (HfO₂) is an inorganic compound and an important high-k dielectric for modern semiconductor technology. It is also used in advanced high-temperature ceramic systems. The material is supplied as a fine, odorless white powder or as a dense sintered body and offers exceptionally high thermal stability.
At room temperature, HfO₂ predominantly crystallizes in a monoclinic structure. At elevated temperatures, it transforms into a tetragonal phase at around 1700 °C and into a cubic phase at still higher temperatures. Hafnium oxide is highly chemically inert and practically insoluble in water, alcoholic media and most acids. It can dissolve, among other conditions, in hydrofluoric acid and concentrated hot sulfuric acid.
One of the key properties of hafnium oxide is its high dielectric constant of approximately 25 combined with a wide band gap of around 5.3-5.7 eV. This combination makes HfO₂ suitable for extremely thin insulating layers in field-effect transistors while helping to reduce leakage currents and maintain high capacitance.
Hafnium oxide also has a high refractive index of approximately 2.1 and good optical transparency from the near-ultraviolet into the mid-infrared region. These properties make it useful in interference filters, laser mirrors and advanced multilayer optical coatings.
Industrial HfO₂ can be produced by thermal decomposition of hafnium nitrate or hafnium oxalate. For functional thin films used in microelectronics, atomic layer deposition (ALD) with volatile hafnium precursors is also widely applied.
Hafnium and its compounds are particularly important in microelectronics, optical coatings, specialty ceramics, sensors and high-temperature technologies. Would you like to buy hafnium oxide? Auremo can provide information about available purity grades, product forms and delivery conditions. The hafnium price, hafnium metal price and hafnium price per kg primarily refer to metallic hafnium, while the hafnium oxide price depends on purity, material form and order quantity.
Advantages
• High dielectric constant for high-k applications
• Supports reduced leakage currents in thin insulating layers
• Exceptionally high thermal stability
• Melting point of approximately 2758 °C
• Wide band gap of approximately 5.3-5.7 eV
• High refractive index of approximately 2.1
• Good optical transparency from near-UV to mid-IR
• High chemical resistance
Applications
• High-k dielectrics in microelectronics
• Integrated circuits, CPUs and GPUs
• DRAM and RRAM structures
• Field-effect transistors
• Interference optical filters
• Laser mirrors
• Antireflective coatings
• Specialty and refractory ceramics
• Thermal barrier coatings
• Crucibles for high-purity synthesis
• Cutting ceramics
• Neutron-absorbing materials
• Functional thin-film gas sensors
Auremo offers hafnium oxide and other high-purity specialty materials for industrial and advanced technical applications. If you have any questions about HfO₂, available purity grades, product forms or delivery conditions, please contact us directly.
