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

Nehate, Shraddha Dhanraj; Saikumar, Ashwin Kumar; Sundaram, Kalpathy B.

doi:10.3390/coatings11020196

Cited by 4 publications

(6 citation statements)

References 39 publications

(48 reference statements)

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“…The lowest band gaps equal to 1.4 and 1.1 eV were reached for the B75 and B100 samples, respectively. These results are in good agreement with the literature data [20,74].…”

Section: Functional Properties Of Filmssupporting

confidence: 93%

Room-Temperature Formation of Hard BCx Films by Low Power Magnetron Sputtering

2021

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Boron carbide is one of the most important non-metallic materials. Amorphous BCx films were synthesized at room temperature by single- and dual-target magnetron sputtering processes. A B4C target and C target were operated using an RF signal and a DC signal, respectively. The effect of using single- and dual-target deposition and process parameters on the chemical bonding and composition of the films as well as their functional properties were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray energy dispersive analysis, X-ray diffraction, ellipsometry, and spectrophotometry. It was found that the film properties depend on the sputtering power and the used targets. EDX data show that the composition of the samples varied from B2C to practically BC2 in the case of using an additional C target. According to the XPS data, it corresponds to the different chemical states of the boron atom. A nanoindentation study showed that the film with a composition close to B2C deposited with the highest B4C target power reached a hardness of 25 GPa and Young’s modulus of 230 GPa. The optical properties of the films also depend on the composition, so the band gap (Eg) of the BCx film varied in the range of 2.1–2.8 eV, while the Eg of the carbon-rich films decreased to 1.1 eV.

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“…The lowest band gaps equal to 1.4 and 1.1 eV were reached for the B75 and B100 samples, respectively. These results are in good agreement with the literature data [20,74].…”

Section: Functional Properties Of Filmssupporting

confidence: 93%

Room-Temperature Formation of Hard BCx Films by Low Power Magnetron Sputtering

2021

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“…A similar outcome of decrease in k value was observed due to an increase in C-H bonds for BCN films deposited using plasma-enhanced chemical vapor deposition (PECVD) as the films acquired lower polarization. 30,32,57 The lowest dielectric constant of 2 was achieved in this study, which is very close to the least value of k = 1.9 recorded for BCN:H films synthesized using PECVD. 58 Figure 6 shows the electrical resistivity extracted from the I-V characteristics of the MIM devices.…”

Section: Electrical Propertiessupporting

confidence: 81%

“…[29][30][31] Our group has previously reported the influence of 3% hydrogenation on the electrical and optical properties of boron carbide thin films. 31,32 Hydrogenation lowered the dielectric constant of boron carbide films from 6.5 to 3.5. Additionally, materials such as a-Si:H, a-SiC:H, SiCN:H have also reported reduced dielectric constant values due to hydrogenation.…”

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confidence: 99%

Hydrogenation of Boron Carbon Nitride Thin Films for Low-k Dielectric Applications

Nehate

Sundaresh

Peale

et al. 2021

ECS J. Solid State Sci. Technol.

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The influence of hydrogenation on boron carbon nitride (BCN) thin films was investigated for low-k dielectric applications. The BCN thin films were deposited using radio-frequency magnetron sputtering in hydrogen, nitrogen, and argon ambiance. The hydrogen/nitrogen reactive gas flow was varied from 0/10 to 10/10 to achieve a varying range of hydrogen doping. Elemental composition and chemical bonding studies of the films were analyzed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). XPS results confirmed the formation of B-C-N atomic hybridization, and FTIR confirmed the hydrogen doping by evidence of C–H bonds. Metal insulator metal structures were fabricated using Al and BCN thin films to measure electrical properties such as dielectric constant and resistivity. Hydrogenation of BCN caused a 68% decrease in the k value from 6.2 to 2 due to the formation of non-polar bonds. The k value of 2 reported in this study is the lowest value achieved for hydrogenated BCN films deposited by the RF magnetron sputtering technique.

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“…19 Furthermore, according to Bravic et al, the bandgap will decrease with increasing temperature, and they predicted an even lower bandgap of 1.52 eV at zero temperature. 24 Due to the difficulty in measuring and removing surface reflection in ordinary UV−vis transmission spectroscopy, Tauc plots from UV−vis exhibit baseline absorption in many other materials, including amorphous silicon, 25 CdS, 26 hydrogenated boron carbide, 27 ZnO, 28 recent organic−inorganic perovskites 29,30 and all-inorganic perovskites, 31,32 as well as many nanostructured materials. 33−39 In order to obtain accurate values of their bandgaps, these Tauc plots must also be idealized.…”

mentioning

confidence: 99%

“…Due to the difficulty in measuring and removing surface reflection in ordinary UV–vis transmission spectroscopy, Tauc plots from UV–vis exhibit baseline absorption in many other materials, including amorphous silicon, CdS, hydrogenated boron carbide, ZnO, recent organic–inorganic perovskites , and all-inorganic perovskites, , as well as many nanostructured materials. − In order to obtain accurate values of their bandgaps, these Tauc plots must also be idealized. For silicon, Figure S1 in the Supporting Information shows a correction of 33 meV compared with the value obtained from extrapolation to the baseline.…”

mentioning

confidence: 99%

Idealizing Tauc Plot for Accurate Bandgap Determination of Semiconductor with Ultraviolet–Visible Spectroscopy: A Case Study for Cubic Boron Arsenide

Zhong

Pan

Yue

et al. 2023

J. Phys. Chem. Lett.

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The Tauc plot is widely used to determine the bandgap of semiconductors, but the actual plot often exhibits significant baseline absorption below the expected bandgap, leading to bandgap discrepancies from two different extrapolations. In this work, we first discuss the origin of baseline absorption and show that both extrapolation methods can produce significant errors by simulating Tauc plots with varying levels of baseline absorption. We then propose and experimentally verify a new method that idealizes the absorption spectrum by removing its baseline before constructing the Tauc plot. Finally, we apply this new method to cubic boron arsenide (c-BAs), resolve its bandgap discrepancies, and obtain a converging bandgap of 1.835 eV based on both previous and new transmission spectra. The method is applicable to both indirect and direct bandgap semiconductors with absorption spectrum measured via transmission or diffuse reflectance, which will become essential to obtain accurate values of their bandgaps.

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

Cited by 4 publications

References 39 publications

Room-Temperature Formation of Hard BCx Films by Low Power Magnetron Sputtering

Room-Temperature Formation of Hard BCx Films by Low Power Magnetron Sputtering

Hydrogenation of Boron Carbon Nitride Thin Films for Low-k Dielectric Applications

Idealizing Tauc Plot for Accurate Bandgap Determination of Semiconductor with Ultraviolet–Visible Spectroscopy: A Case Study for Cubic Boron Arsenide

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