Thermoelectric properties of boron-carbide thin film and thin film based thermoelectric device fabricated by intense-pulsed ion beam evaporation

Sasaki, Syunsuke; Takeda, M.; Yokoyama, Keiichi; Miura, Takahiro; Suzuki, Tsuneo; Suematsu, Hisayuki; Jiang, Weihua; Yatsui, Kiyoshi

doi:10.1016/j.stam.2004.11.010

Cited by 43 publications

(24 citation statements)

References 10 publications

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“…Boron carbide is a low Z material with series of excellent properties such as high hardness (>30 GPa), high Young's modulus (>300 Gpa), low dielectric constant values ≤5, and high thermal and chemical stability [5][6][7]. As a result, boron carbide is being considered as a possible candidate material for low-k dielectric applications [8,9]. Various techniques have been used to synthesize thin and robust films of boron carbide such as chemical vapor deposition (CVD) [10], laser CVD [11], pulsed laser deposition (PLD) [12], ion beam evaporation [13], radio frequency (RF) magnetron sputtering [14,15], and direct current (DC) magnetron sputtering [16].…”

Section: Introductionmentioning

confidence: 99%

Influence of Substrate Temperature on Electrical and Optical Properties of Hydrogenated Boron Carbide Thin Films Deposited by RF Sputtering

2021

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Amorphous hydrogenated boron carbide films were deposited on silicon and glass substrates using radio frequency sputtering. The substrate temperature was varied from room temperature to 300 °C. The substrate temperature during deposition was found to have significant effects on the electrical and optical properties of the deposited films. X-ray photoelectron spectroscopy (XPS) revealed an increase in sp2-bonded carbon in the films with increasing substrate temperature. Reflection electron energy loss spectroscopy (REELS) was performed in order to detect the presence of hydrogen in the films. Metal-insulator-metal (MIM) structure was developed using Al and hydrogenated boron carbide to measure dielectric value and resistivity. Deposited films exhibited lower dielectric values than pure boron carbide films. With higher substrate deposition temperature, a decreasing trend in dielectric value and resistivity of the films was observed. For different substrate temperatures, the dielectric value of films ranged from 6.5–3.5, and optical bandgap values were between 2.25–2.6 eV.

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Section: Introductionmentioning

confidence: 99%

Influence of Substrate Temperature on Electrical and Optical Properties of Hydrogenated Boron Carbide Thin Films Deposited by RF Sputtering

2021

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“…Its low-Z character (i.e., low electron and mass density), coupled with its robust mechanical, chemical, and thermal properties, render it a candidate for low-κ dielectric material development [17][18][19], a challenge at the forefront of modern integrated circuit interconnect technologies [20,21]. With the right combination of properties, a-B x C:H y may additionally prove suitable for other specialized electronics [22,23] and coatings [24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Tuning the properties of a complex disordered material: Full factorial investigation of PECVD-grown amorphous hydrogenated boron carbide

Nordell

Keck

Nguyen

et al. 2016

Materials Chemistry and Physics

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A multiresponse 2 5 full factorial experiment is performed to investigate the effects of growth conditions (temperature, power, pressure, total flow rate, partial precursor flow rate) on the chemical, mechanical, dielectric, electronic, and charge transport properties of thin-film amorphous hydrogenated boron carbide (a-B x C:H y ) grown by plasma-enhanced chemical vapor deposition (PECVD) from orthocarborane. The main and interaction effects are determined and discussed, and the relationships between properties are investigated via correlation analysis. The process condition with the strongest influence on growth rate is pressure, followed by partial precursor flow rate, with low pressure and high partial flow rate conditions yielding the highest growth rates. The atomic concentration of hydrogen (at.% H) and density are controlled primarily by temperature and power, with low temperature and power conditions leading to relatively soft, hydrogen-rich, low-density, porous films, and vice versa. The B/C ratio is controlled by temperature, power, pressure, and the power*pressure interaction, and is uncorrelated to hydrogen concentration. Thin-film dielectric and electronic structure properties, including high-frequency dielectric constant (ε 1 ), low-frequency/total dielectric constant (κ), optical band gap (E Tauc /E 04 ), and Urbach energy (E U ), are correlated strongly with at.% H, and weakly to moderately with B/C ratio. These properties are dominated by the influence of temperature, with a second significant influence from the power*pressure interaction. The interaction of power and pressure leads to two opposite growth regimes-high power and high pressure or low power and low pressure-that can produce a-B x C:H y films with similar dielectric or electronic structure properties. Charge transport properties also show a correlation with at.% H and B/C, but not with the electronic structure and disorder parameters, which suggests a complicated relationship between the two. The range of properties measured highlights the potential of thin-film a-B x C:H y for low-κ dielectric and neutron detection applications, and suggests clear pathways for future material property optimization.

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“…The problem with employing such bulk growth techniques for the specialized semiconductor device applications described above is that they require harsh fabrication conditions, demonstrate limited tunability, and tend to yield unfavorable electronic properties such as unacceptably high electrical conductivity. 26,27 It has been demonstrated [28][29][30][31][32][33][34] that the use of thin-film fabrication methods such as chemical vapor deposition or physical vapor deposition can produce B x C thin films that maintain robust mechanical, thermal, and chemical properties, while improving on electrical transport, electronic, and/or optical properties (e.g., resistivity and band gap), without having to resort to the extreme conditions required by traditional bulk growth techniques. In particular, the plasma-enhanced chemical vapor deposition (PECVD) of films from ortho-carborane (o-C 2 B 10 H 12 ), which typically yields amorphous hydrogenated boron carbide (a-B x C:H y ) when lower growth temperatures are used, has been shown to be suitable for producing films for device applications as well as conducive to tuning properties over a wide range.…”

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confidence: 99%

The influence of hydrogen on the chemical, mechanical, optical/electronic, and electrical transport properties of amorphous hydrogenated boron carbide

Nordell

Karki

Nguyen

et al. 2015

Journal of Applied Physics

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Because of its high electrical resistivity, low dielectric constant (j), high thermal neutron capture cross section, and robust chemical, thermal, and mechanical properties, amorphous hydrogenated boron carbide (a-B x C:H y) has garnered interest as a material for low-j dielectric and solid-state neutron detection applications. Herein, we investigate the relationships between chemical structure (atomic concentration B, C, H, and O), physical/mechanical properties (density, porosity, hardness, and Young's modulus), electronic structure [band gap, Urbach energy (E U), and Tauc parameter (B 1/2)], optical/dielectric properties (frequency-dependent dielectric constant), and electrical transport properties (resistivity and leakage current) through the analysis of a large series of a-B x C:H y thin films grown by plasma-enhanced chemical vapor deposition from ortho-carborane. The resulting films exhibit a wide range of properties including H concentration from 10% to 45%, density from 0.9 to 2.3 g/cm 3 , Young's modulus from 10 to 340 GPa, band gap from 1.7 to 3.8 eV, Urbach energy from 0.1 to 0.7 eV, dielectric constant from 3.1 to 7.6, and electrical resistivity from 10 10 to 10 15 X cm. Hydrogen concentration is found to correlate directly with thin-film density, and both are used to map and explain the other material properties. Hardness and Young's modulus exhibit a direct power law relationship with density above $1.3 g/cm 3 (or below $35% H), below which they plateau, providing evidence for a rigidity percolation threshold. An increase in band gap and decrease in dielectric constant with increasing H concentration are explained by a decrease in network connectivity as well as mass/electron density. An increase in disorder, as measured by the parameters E U and B 1/2 , with increasing H concentration is explained by the release of strain in the network and associated decrease in structural disorder. All of these correlations in a-B x C:H y are found to be very similar to those observed in amorphous hydrogenated silicon (a-Si:H), which suggests parallels between the influence of hydrogenation on their material properties and possible avenues for optimization. Finally, an increase in electrical resistivity with increasing H at <35 at. % H concentration is explained, not by disorder as in a-Si:H, but rather by a lower rate of hopping associated with a lower density of sites, assuming a variable range hopping mechanism interpreted in the framework of percolation theory. V

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Thermoelectric properties of boron-carbide thin film and thin film based thermoelectric device fabricated by intense-pulsed ion beam evaporation

Cited by 43 publications

References 10 publications

Influence of Substrate Temperature on Electrical and Optical Properties of Hydrogenated Boron Carbide Thin Films Deposited by RF Sputtering

Influence of Substrate Temperature on Electrical and Optical Properties of Hydrogenated Boron Carbide Thin Films Deposited by RF Sputtering

Tuning the properties of a complex disordered material: Full factorial investigation of PECVD-grown amorphous hydrogenated boron carbide

The influence of hydrogen on the chemical, mechanical, optical/electronic, and electrical transport properties of amorphous hydrogenated boron carbide

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