Effects of substrate bias and nitrogen flow ratio on the resistivity, composition, crystal structure, and reflectance of reactively sputtered hafnium-nitride film

Jeng, Jiann Shing; Liu, Chin‐Hung; Chen, Jen‐Sue

doi:10.1016/j.jallcom.2009.07.023

Cited by 11 publications

(8 citation statements)

References 22 publications

(22 reference statements)

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“…It is worth noting that although the phenomenon that optical reflectivity properties in δ-TiN x and δ-ZrN x films depends strongly on stoichiometry has been observed, the underlying mechanism has not been well explored yet. Furthermore, so far, a systematic investigation concerning the effects of stoichiometry on the optical reflectivity properties of δ-HfN x films is still lacking, though the effects of certain deposition parameters including substrate temperature 14 and substrate bias 24 have been previously reported.…”

Section: Introductionmentioning

confidence: 99%

“…Extensive researches on the optical reflectivity properties for δ-TiN x , − δ-ZrN x ,− and δ-HfN x ,, films, prepared by magnetron sputtering or pulsed laser deposition, have been performed. It has been found in δ-TiN x and δ-ZrN x films that the stoichiometry x is an important factor in determining optical reflectivity feature.…”

Section: Introductionmentioning

confidence: 99%

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Nature of Tunable Optical Reflectivity of Rocksalt Hafnium Nitride Films

Wang

et al. 2014

J. Phys. Chem. C

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Although the phenomenon that optical reflectivity of hard group IVB transition metal nitrides depends on stoichiometry has been reported, the microscopic origin of this behavior has not been well explored yet. Here we find that optical reflectivity of rocksalt hafnium nitride films (δ-HfN x ) can be effectively tuned by stoichiometry x, and the underlying mechanism can be well elucidated by Drude−Lorentz fitting and first-principles calculations. It is shown that the observed tunability of optical reflectivity arises from a transition from N vacancies (V N ) to Hf vacancies (V Hf ) in the films because this evolution from V N to V Hf has important roles in changing electronic properties of the films in the following three aspects: (i) density of free electrons, wherein V N and V Hf act as donor-like and acceptor-like defects, respectively; (ii) mean free path of free electrons, in which V N and V Hf are the main electron scattering sites in sub-and overstoichiometric films, respectively; (iii) interband transition absorption of bound electrons, wherein three previously unreported absorption bands originating from V N and V Hf are found to occur at ∼0.81, 2.27, and 3.75 eV. These point-defect-induced variations significantly affect the dielectric function of δ-HfN x films and thus drive the tailored evolution in reflectivity properties with x.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nature of Tunable Optical Reflectivity of Rocksalt Hafnium Nitride Films

Wang

et al. 2014

J. Phys. Chem. C

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“…The results confirm the presence of nitrogen, chromium and titanium in the coatings. It should be also noted that in all the coatings, the presence of oxygen (up to 11.5 at.%), which is possibly due to the adsorbed residual oxygen during deposition [21]. Also, the results indicates that increase in Ar/N 2 ratio results in decrease of the content of N atoms in the coatings from about 36 to 13.5 at.%.…”

Section: Chemical Composition and Deposition Ratementioning

confidence: 69%

“…In the stage III, the flow and energy of ions flux of sputter-ejected species increase further as the Ar/N2 ratio (>3) increases. As a result of the substantial increase in deposition rate, the adsorbed oxygen impurities can be easily re-sputtered by the incident ions particles, especially Ar + [21] however, the concentration of oxygen decreased to 6.2 at.% for Ar/N 2 = 4. Finally, since the chemical composition and velocity of the deposited species play a significant role in the film properties, these stages are important for the following discussion.…”

Section: Chemical Composition and Deposition Ratementioning

confidence: 99%

Effect of Ar/N2 flow ratio on the microstructure and mechanical properties of Ti-Cr-N coatings deposited by DC magnetron sputtering on AISI D2 tool steels

Kehal¹,

Saoula²,

Abaidia³

et al. 2021

Surface and Coatings Technology

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Ti-Cr-N coatings were deposited on Si (100) and AISI D2 tool steel substrates by reactive DC magnetron cosputtering technique from titanium and chromium target in mixed Ar/N 2 atmosphere. The Ar/N 2 ratio effects on the chemical composition, structure, morphology, intrinsic stress and mechanical properties of the Ti-Cr-N coatings were investigated. The growing process of Ti-Cr-N coatings can be divided into three stages: Stage I, in poisoning mode (low flow ratio 1 < Ar/N 2 ≤ 1.4), Stage II, in transition mode (intermediate flow ratio 1.4 ≤ Ar/N 2 ≤ 3) and Stage III in metallic mode (Ar/N 2 > 3). For all samples, XRD analysis shown the formation of mixed nitrides phases. In stage I, Ti 2 N, TiN 0.3 , and hexagonal-Cr 2 N phases were observed. In Stage II, TiN 0.3 , Cr 2 N, and cubic-TiN phases were formed, while only TiN and Cr 2 N are observed in stage III. The coatings deposited with Ar/N₂ ratio of 3 shows the largest hardness of 24 GPa which is attribute to the dense structure and smoother surface morphology. The properties of the films are discussed in terms of evolution growth stages resulting by the variation of Ar/N 2 flow ratios.

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“…In near-stoichiometric films, a significant increase in the electron mean free path leads to higher reflectivity. Negative substrate bias also improves optical reflectivity due to reduced nitrogen and hafnium vacancies in the film. , Similarly, the optical properties of ZrN are also improved by tuning the growth parameters. − However, simultaneous tuning of all of the growth parameters to achieve the highest optical reflectivity achievable in HfN and ZrN films remains unexplored. In this work, we demonstrate record-high solar and infrared reflectance of epitaxial stoichiometric HfN and ZrN thin films by optimizing all of the growth parameters.…”

Section: Introductionmentioning

confidence: 99%

Refractory Plasmonic Hafnium Nitride and Zirconium Nitride Thin Films as Alternatives to Silver for Solar Mirror Applications

Das

Biswas

Maurya

et al. 2022

ACS Appl. Mater. Interfaces

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Harnessing solar energy by employing concentrated solar power (CSP) systems requires materials with high electrical conductivity and optical reflectivity. Silver, with its excellent optical reflectance, is traditionally used as a reflective layer in solar mirrors for CSP technologies. However, silver is soft and expensive, quickly tarnishes, and requires a protective layer of glass for practical applications. Moreover, supply-side constraints and high-temperature instability of silver have led to the search for alternative materials that exhibit high solar and infrared reflectance. Transition metal nitrides, such as titanium nitride, have emerged as alternative plasmonic materials to gold starting from a spectral range of ∼500 nm. However, to achieve high solar reflection (∼320–2500 nm), materials with epsilon-near-zero starting from the near-ultraviolet (UV) spectral region are required. Here, we show the development of refractory epitaxial hafnium nitride (HfN) and zirconium nitride (ZrN) thin films as excellent mirrors with a solar reflectivity of ∼90.3% and an infrared reflectivity of ∼95%. Low-loss and high-quality epsilon-near-zero resonance at near-UV (∼340–380 nm) spectral regions are achieved in HfN and ZrN by carefully controlling the stoichiometry, leading to a sharp increase in the reflection edge that is on par with silver. Temperature-dependent reflectivity and dielectric constants are further measured to demonstrate their high-temperature suitability. The development of refractory epitaxial HfN and ZrN thin films with high solar and infrared reflectance makes them excellent alternative plasmonic materials to silver and would pave their applications in CSP, daytime radiative cooling, and others.

show abstract

Effects of substrate bias and nitrogen flow ratio on the resistivity, composition, crystal structure, and reflectance of reactively sputtered hafnium-nitride film

Cited by 11 publications

References 22 publications

Nature of Tunable Optical Reflectivity of Rocksalt Hafnium Nitride Films

Nature of Tunable Optical Reflectivity of Rocksalt Hafnium Nitride Films

Effect of Ar/N2 flow ratio on the microstructure and mechanical properties of Ti-Cr-N coatings deposited by DC magnetron sputtering on AISI D2 tool steels

Refractory Plasmonic Hafnium Nitride and Zirconium Nitride Thin Films as Alternatives to Silver for Solar Mirror Applications

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