Materials - Hafnium dioxide layers

Hafnium dioxide layers

Description

Hafnium dioxide (HfO₂), also known as hafnia, thin films are obtained by atomic layer deposition (ALD) on range of substrates, like Si, GaN, SiC, graphene, SiO₂ etc. The material is formed in a double exchange chemical reaction between two reactants (precursors), such as a deionized water (oxygen precursor) and a tetrakis(dimetylamido)hafnium(IV) - TDMAH (hafnium precursor). HfO₂ can be grown at the temperature range from 70°C to 300°C. The maximum size of the substrate is 20 cm of a diameter.

Specification

Thickness: 10 - 3000 nm
Growth rate: 0.2 nm/minute
Resistivity: > 10⁸ Ωcm
Energy gap: 6.2 eV
Refractive index: 2.03 (635 nm)
Relative permittivity: 21±3
Hydrophobic properties
Surface roughness: 0.4 nm < RMS < 30 nm
Structure: polycrystalline - monoclinic phase or amorphous layers
Average transmission in visible spectra:> 80%
Uniformity of coatings

Applications

HfO₂ is characterized by good optical, electrical and structural properties, therefore this material can be used as an insulator in electronic devices especially in "transparent electronics", as a variable resistance material in electronic memories, as optical coatings with high refractive indices in lasers and microscopes and as a protective or barrier layers of photovoltaic structures. In addition, this material can be used in medicine and dentistry for the manufacture of prostheses and implants.

Cross-section image of HfO₂ on silicon substrate from scanning electron microscope (SEM).

HfO₂ surface image (with RMS: 0.4 nm) on silicon substrate from atomic force microscope (AFM).

X-ray diffraction pattern (XRD) of polycrystalline in the monoclinic phase hafnia layers . The layers were grown on a glass substrate.