A study of some optical properties of hafnium dioxide (HfO 2 ) thin films and their applications

Fadel, M.; M., O.A. Azim; Omer, O.A.; Basily, R.R.

doi:10.1007/s003390050675

Cited by 66 publications

(39 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In spite of the relatively scarce literature about its optical properties, hafnium oxide has interesting optical applications. For example, due to the large band gap and high refractive index it has been used as optical coatings for astronomical CCDs [24] and as antireflective multi-layer coatings for night vision devices and for IR optical devices [25].…”

Section: Introductionmentioning

confidence: 99%

Optical properties and structure of HfO₂thin films grown by high pressure reactive sputtering

Martínez¹,

Toledano-Luque²,

Gandı́a³

et al. 2007

J. Phys. D: Appl. Phys.

162

View full text Add to dashboard Cite

Thin films of hafnium oxide have been grown by high pressure reactive sputtering on transparent quartz substrates (UV-grade silica) and silicon wafers. Deposition conditions were adjusted to obtain polycrystalline as well as amorphous films. Optical properties of the films deposited on the silica substrates were investigated by transmittance and reflectance spectroscopy in the ultraviolet, visible and near infrared range (UV-VIS-NIR). A numerical analysis method that takes into account the different surface roughness of the polycrystalline and amorphous films was applied to calculate the optical constants (refractive index and absorption coefficient). Amorphous films were found to have a higher refractive index and a lower transparency than polycrystalline films. This is attributed to a higher density of the amorphous samples, which was confirmed by atomic density measurements performed by heavy-ion elastic recoil detection analysis (ERDA). The absorption coefficient gave an excellent fit to the Tauc law (indirect gap), which allowed to obtain a band gap value of 5.54 eV. The structure of the films (amorphous or polycrystalline) was found to have no significant influence on the nature of the band gap. The Tauc plots also give information about the structure of the films, because the slope of the plot (the Tauc parameter) is related to the degree of order in the bond network. The amorphous samples had a larger value of the Tauc parameter, i.e., more order than the polycrystalline samples. This is indicative of a uniform bond network with percolation of the bond chains, in contrast to the randomly oriented polycrystalline grains separated by grain boundaries.2

show abstract

Section: Introductionmentioning

confidence: 99%

Optical properties and structure of HfO₂thin films grown by high pressure reactive sputtering

Martínez¹,

Toledano-Luque²,

Gandı́a³

et al. 2007

J. Phys. D: Appl. Phys.

162

View full text Add to dashboard Cite

show abstract

“…HfO 2 is regularly used as optical coating for astronomical charge coupled devices ͑CCDs͒, 3 as antireflective multilayer coating for night vision devices, and for IR optical devices. 4 Moreover, HfO 2 is used in pH, Na + , K + , and H + chemical sensors, 5 and in physical sensors for on chip temperature detection. 6 The application of high-k materials in bioelectronics has also been studied due to the efficient capacitive interaction of silicon chips and living cells.…”

Section: Introductionmentioning

confidence: 99%

High-pressure reactively sputtered HfO2: Composition, morphology, and optical properties

Toledano-Luque

Andrés

Prado

et al. 2007

Journal of Applied Physics

View full text Add to dashboard Cite

Hafnium oxide films were deposited by high pressure reactive sputtering using different deposition pressures and times. The composition, morphology, and optical properties of the films, together with the sputtering process growth kinetics were investigated using heavy ion elastic recoil detection analysis, Fourier transform infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, x-ray diffraction, and transmission electron microscopy. The films showed a monoclinic polycrystalline structure, with a grain size depending on the deposition pressure. All films were slightly oxygen rich with respect to stoichiometric HfO 2 and presented a significant amount of hydrogen ͑up to 6 at. %͒, which is attributed to the high affinity for moisture of the HfO 2 films. The absorption coefficient was fitted to the Tauc law, obtaining a band gap value of 5.54 eV. It was found that the growth rate of the HfO 2 films depends on the deposition pressure ͑P͒ as P −1.75 . This dependence is explained by a diffusion model of the thermalized atoms in high-pressure sputtering. Additionally, the formation of an interfacial silicon oxide layer when the films were grown on silicon was observed, with a minimum thickness for deposition pressures around 1.2 mbars. This interfacial layer was formed mainly during the initial stages of the deposition process, with only a slight increase in thickness afterwards. These results are explained by the oxidizing action of the oxygen plasma and the diffusion of oxygen radicals and hydroxyl groups through the polycrystalline HfO 2 film. Finally, the dielectric properties of the HfO 2 / SiO 2 stacks were studied by means of conductance and capacitance measurements on Al/ HfO 2 / SiO 2 / Si devices as a function of gate voltage and ac frequency signal.

show abstract

“…This is in excellent agreement with published data for HfO 2 films. 19,21,22,25 The crystal structure of HfO 2 thin film, deposited on silicon (100) single crystal wafer, is represented by XRD data shown in figure-1, where the dashed vertical lines represent the characteristic peaks for the HfO 2 monoclinic phase. 26 The film is polycrystalline and the Scherrer equation provides 8-10 nm for the average grain size in the film.…”

Section: -2mentioning

confidence: 99%

“…In comparison to the Si 3 N 4 dielectric, [13][14][15][16][17] hafnium dioxide offers several attractive properties. For example, HfO 2 is characterized with 4-6 times higher dielectric constant, optical transparency over much wider range of wavelengths (250-2000 nm), 3 times higher density in the solid state, chemical stability, and very high melting point 2758 0 C. [18][19][20][21][22] The high dielectric constant and good optical transparency over wider wavelength range are useful for high sensitivity waveguide coupled bimetallic (WCBM) sensors working in VIS-IR range. The surface plasmon polaritons are characterized by a wavevector…”

mentioning

confidence: 99%

Hafnium dioxide as a dielectric for highly-sensitive waveguide-coupled surface plasmon resonance sensors

Tiwari

Sharma

Hozhabri³

2016

AIP Advances

View full text Add to dashboard Cite

Hafnium dioxide has been recognized as an excellent dielectric for microelectronics. However, its usefulness for the surface plasmon based sensors has not yet been tested. Here we investigate its usefulness for waveguide-coupled bi-metallic surface plasmon resonance sensors. Several Ag/HfO2/Au multilayer structure sensors were fabricated and evaluated by optical measurements and computer simulations. The resulting data establish correlations between the growth parameters and sensor performance. The sensor sensitivity to refractive index of analytes is determined to be Sn=∂θSPR∂n≥470. The sensitivity data are supported by simulations, which also predict 314 nm for the evanescent field decay length in air.

show abstract

A study of some optical properties of hafnium dioxide (HfO 2 ) thin films and their applications

Cited by 66 publications

References 2 publications

Optical properties and structure of HfO₂thin films grown by high pressure reactive sputtering

Optical properties and structure of HfO₂thin films grown by high pressure reactive sputtering

High-pressure reactively sputtered HfO2: Composition, morphology, and optical properties

Hafnium dioxide as a dielectric for highly-sensitive waveguide-coupled surface plasmon resonance sensors

Contact Info

Product

Resources

About

A study of some optical properties of hafnium dioxide (HfO 2 ) thin films and their applications

Cited by 66 publications

References 2 publications

Optical properties and structure of HfO2thin films grown by high pressure reactive sputtering

Optical properties and structure of HfO2thin films grown by high pressure reactive sputtering

High-pressure reactively sputtered HfO2: Composition, morphology, and optical properties

Hafnium dioxide as a dielectric for highly-sensitive waveguide-coupled surface plasmon resonance sensors

Contact Info

Product

Resources

About

Optical properties and structure of HfO₂thin films grown by high pressure reactive sputtering

Optical properties and structure of HfO₂thin films grown by high pressure reactive sputtering