Effect of Nitrogen Flow on the Growth of Nitrogen Ultrananocrystalline Diamond (N-UNCD) Films on Si/SiO2/HfO2 Substrate

Villarreal, Daniel; Wittel, Frederick P.; Rajan, Anusha; Wittel, Phillip; Alcantar-Peña, Jesús J.; Auciello, Orlando; Obaldía, Elida de

doi:10.1109/iestec46403.2019.00023

Cited by 2 publications

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“…The Raman spectrum reveals peaks at 1345 cm −1 , which encapsulates the 1332 cm −1 peak correlated with sp 3 C atoms bonds characteristic of diamond in the grains, and sp 2 bonds of C atoms in the grain boundaries, expected for N-UNCD films, as shown in those grown by MPCVD [ 16 ]. The Raman spectrum shown in Figure 3 c and Figure 4 c,d are considered N-UNCD thin films, since they show the TPA peaks at 1150 ane1480 cm-1 characteristic of UNCD films [ 17 ], although the D and G peaks are a bit sharper and higher than the peaks observed in thick N-UNCD films produced by MPCVD [ 5 , 6 ] or thicker N-UNCD films grown recently by HFCVD [ 8 , 18 ] on Si substrate. This may be due to the laser beam reaching the underlying graphite layer used as substrate.…”

Section: Resultsmentioning

confidence: 99%

“…This limits the energy space, which must be supplied by the Hot Filament. Nitrogen can also compete with growth sites, making the growth of N-UNCD less efficient than for UNCD [ 8 ].…”

Section: Discussionmentioning

confidence: 99%

“…In previous research, a mixture of gases (H 2 4.0 sccm/CH 4 1.0 sccm/Ar: 5.0 sccm/N 2 6.0 sccm), demonstrated the feasibility for growing N-UNCD films by HFCVD [ 8 , 9 ]. However, the effect of filament-substrate distance, thus travel distance for precursor species described above, the temperature of the substrate surface, and gas pressure to grow N-UNCD films, have not been studied.…”

Section: Introductionmentioning

confidence: 99%

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Growth of Nitrogen Incorporated Ultrananocrystalline Diamond Coating on Graphite by Hot Filament Chemical Vapor Deposition

et al. 2022

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This article shows the results of experiments to grow Nitrogen incorporated ultrananocrystalline diamond (N-UNCD) films on commercial natural graphite (NG)/Cu anodes by hot chemical vapor deposition (HFCVD) using a gas mixture of Ar/CH4/N2/H2. The experiments focused on studying the effect of the pressure in the HFCVD chamber, filament-substrate distance, and temperature of the substrate. It was found that a substrate distance of 3.0 cm and a substrate temperature of 575 C were optimal to grow N-UNCD film on the graphite surface as determined by Raman spectroscopy, SEM, and TEM imaging. XPS analysis shows N incorporation through the film. Subsequently, the substrate surface temperature was increased using a heater, while keeping the substrate-filament distance constant at 3.0 cm. In this case, Raman spectra and SEM images of the substrate surface showed a major composition of graphite in the film as the substrate-surface temperature increased. Finally, the process pressure was increased to 10 Torr where it was seen that the growth of N-UNCD film occurred at 2.0 cm at a substrate temperature of 675 C. These results suggest that as the process pressure increases a smaller substrate-filament distance and consequently a higher substrate surface temperature can still enable the N-UNCD film growth by HFCVD. This effect is explained by a mean free path analysis of the main precursors H2 and CH3 molecules traveling from the filament to the surface of the substrate The potential impact of the process developed to grow electrically conductive N-UNCD films using the relatively low-cost HFCVD process is that this process can be used to grow N-UNCD films on commercial NG/Cu anodes for Li-ion batteries (LIBs), to enable longer stable capacity energy vs. charge/discharge cycles.

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Section: Resultsmentioning

confidence: 99%

“…This limits the energy space, which must be supplied by the Hot Filament. Nitrogen can also compete with growth sites, making the growth of N-UNCD less efficient than for UNCD [ 8 ].…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Growth of Nitrogen Incorporated Ultrananocrystalline Diamond Coating on Graphite by Hot Filament Chemical Vapor Deposition

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“…The initial UNCD growth forms hemispherical structures which then merge into a continuous film. The large presence of D* and G for UNCD could be due to filling between the cluster of crystals (up to~1 µm) that is typical in UNCD film growth [12,26].…”

Section: Raman Analysismentioning

confidence: 99%

Study of Atomic Hydrogen Concentration in Grain Boundaries of Polycrystalline Diamond Thin Films

et al. 2021

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This paper describes research focused on investigating the effect of hydrogen (H) atom insertion into the grain boundaries of polycrystalline diamond (PCD) films. This is required in order to understand the key morphological, chemical, physical, and electronic properties of the films. The PCD films were grown using the hot filament chemical vapor deposition (HFCVD) process, with flowing Ar gas mixed with CH4 and H2 gases to control film growth into microcrystalline diamond (MCD, 0.5–3 µm grain sizes), nanocrystalline diamond (NCD, 10–500 nm grain sizes), and ultrananocrystalline diamond (UNCD, 2–5 nm grain sizes) films depending on the Ar/CH4/H2 flow ratios. This study focused on measuring the H atom concentration of the PCD films to determine the effect on the properties indicated above. A simple model is presented, including a hypothesis that the two dangling bonds per unit cell of C atoms serve as the site of hydrogen incorporation. This correlates well with the observed concentration of H atoms in the films. Dangling bonds which are not passivated by hydrogen are postulated to form surface structures which include C double bonds. The Raman peak from these surface structures are the same as observed for transpolyacetyline (TPA). The data reveal that the concentration of H atoms at the grain boundaries is around 1.5 × 1015 atoms/cm2 regardless of grain size. Electrical current measurements, using a conductive atomic force microscopy (CAFM) technique, were performed using an MCD film, showing that the current is concentrated at the grain boundaries. Ultraviolet photo electron spectroscopy (UPS) confirmed that all the PCD films exhibited a metallic behavior. This is to be expected if the nature of grain boundaries is the same regardless of grain size.

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Effect of Nitrogen Flow on the Growth of Nitrogen Ultrananocrystalline Diamond (N-UNCD) Films on Si/SiO2/HfO2 Substrate

Cited by 2 publications

References 16 publications

Growth of Nitrogen Incorporated Ultrananocrystalline Diamond Coating on Graphite by Hot Filament Chemical Vapor Deposition

Growth of Nitrogen Incorporated Ultrananocrystalline Diamond Coating on Graphite by Hot Filament Chemical Vapor Deposition

Study of Atomic Hydrogen Concentration in Grain Boundaries of Polycrystalline Diamond Thin Films

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