Bias enhanced nucleation of diamond on silicon (100) in a HFCVD system

Janischowsky, K.; Ebert, Wolfgang; Kohn, E.

doi:10.1016/s0925-9635(02)00294-7

Cited by 56 publications

(23 citation statements)

References 15 publications

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“…The deposition of the NCD film on a foreign substrate is a 2 steps process consisting on a nucleation phase, followed by an overgrowth stage. The HF-NCD samples were nucleated under similar conditions to the ones described in ref [25] by bias enhanced nucleation 50 (BEN) performed in-situ in the same reactor used for the overgrowth, resulting in crystallite densities of more than 10 10 cm 2 . For the MW-NCD samples the seeding process described in ref [26] was used to form the nucleation layer.…”

Section: Methodsmentioning

confidence: 99%

Control of the in-plane thermal conductivity of ultra-thin nanocrystalline diamond films through the grain and grain boundary properties

et al. 2016

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The in-plane thermal conductivity of polycrystalline diamond near its nucleation site, which is a key parameter to an efficient integration of diamond in modern high power AlGaN/GaN high electron mobility devices, has been studied. By controlling the lateral grain size evolution through the diamond growth conditions it has been possible to increase the in-plane thermal conductivity of the polycrystalline diamond film for a given thickness. Besides, the in-plane thermal conductivity has been found strongly inhomogeneous across the diamond films, being also possible to control this inhomogeneity by the growth conditions. The experimental results has been explained through a combined effect of the phonon mean free path confinement due the grain size and the quality of the grain/grain interfaces, showing that both effects evolve with the grain expansion and are dependant on the diamond growth conditions. This analysis shows how the thermal transport in the near nucleation region of polycrystalline diamond can be controlled, which ultimately opens the door to create ultra-thin layers with a engineered thermal conductivity, ranging from a few W/mK to a few hundreds of W/mK.

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Section: Methodsmentioning

confidence: 99%

Control of the in-plane thermal conductivity of ultra-thin nanocrystalline diamond films through the grain and grain boundary properties

et al. 2016

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“…The formation of nanodiamond nuclei was driven by Bias Enhanced Nucleation (BEN) in a HFCVD (Hot Filament CVD) system (Janischowsky et al, 2003), while processing the substrate at a temperature of 800 • C in an atmosphere of 0.75% CH 4 in H 2 at a pressure of 1.5 kPa, yielding a nucleation density of approximately 3 × 10 10 cm −2 . Onto this substrate a 200 nm layer of intrinsic NCD was grown, keeping the substrate at a temperature of ∼740 • C in a gas mixture of 0.3% CH 4 in H 2 , at a pressure 2.5 kPa.…”

Section: Device Fabrication and Designmentioning

confidence: 99%

Nanocrystalline diamond microelectrode arrays fabricated on sapphire technology for high-time resolution of quantal catecholamine secretion from chromaffin cells

Carabelli

Gosso

Marcantoni

et al. 2010

Biosensors and Bioelectronics

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a b s t r a c tThe quantal release of oxidizable molecules can be successfully monitored by means of polarized carbon fiber microelectrodes (CFEs) positioned in close proximity to the cell membrane. To partially overcome certain CFE limitations, mainly related to their low spatial resolution and lack of optical transparency, we developed a planar boron-doped nanocrystalline diamond (NCD) prototype, grown on a transparent sapphire wafer. Responsiveness to applied catecholamines as well as the electrochemical and optical properties of the NCD-based device were first characterized by cyclic voltammetry and optical transmittance measurements. By stimulating chromaffin cells positioned on the device with external KCl, well-resolved quantal exocytotic events could be detected either from one NCD microelectrode, or simultaneously from an array of four microelectrodes, indicating that the chip is able to monitor secretory events (amperometric spikes) from a number of isolated chromaffin cells. Spikes detected by the planar NCD device had comparable amplitudes, kinetics and vesicle diameter distributions as those measured by conventional CFEs from the same chromaffin cell.

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“…Due to the need of a conductive substrate to perform BEN, thin conductive interlayers were deposited on the sapphire to be used as a nucleation layer for the growth of the undoped NCD buffer layer; the interlayers materials and thicknesses were tuned in order to minimize light absorption and to maximize the nucleation density [30]. This process led to a nucleation density of approximately 3 × 10 10 cm −2 , comparable with nucleation densities on standard Si wafers [31]. The BEN process was carried out with the following parameters: substrate temperature 800°C, CH 4 to H 2 ratio 0.75%, pressure of 1.5 kPa.…”

Section: Methodsmentioning

confidence: 99%

Fabrication of a NCD microelectrode array for amperometric detection with micrometer spatial resolution

Colombo

Men

Scharpf

et al. 2011

Diamond and Related Materials

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We report on the fabrication of a boron-doped nanocrystalline diamond (NCD) 3 × 3 high-density microelectrode array (MEA) for amperometric measurements, with a single electrode area of 3 × 5 μm 2 and a separation in the μm scale. The NCD microelectrodes were grown by hot filament chemical vapor deposition (HFCVD) on a double-side polished sapphire wafer in order to preserve the diamond transparency. Bias enhanced nucleation (BEN) was performed to ensure a covalent adhesion of the films to the substrate. A current background noise of less than 5 pA peak to peak over a 1 kHz bandwidth resulted from an electrochemical investigation of the new device, using 100 mM KCl solutions and ferrocyanide red-ox couples. Cyclic voltammetry measurements in physiological buffer solution and in the presence of oxidizable biomolecules strengthened its suitability for bio-sensing. When compared to a 2 × 2 NCD microelectrode array prototype, already used for in vitro cell measurements, the signal to noise ratio of the amperometric response of the new 3 × 3 device proved twice as good. In addition, the optical transmittance of the boron-doped thin layers exceeded 40% in the visible wavelength range. The excellent electrochemical properties of NCD electrodes and the transparency in combination with the high spatial resolution make the new 3 × 3 NCD MEA a promising tool for electrochemical sensing in a variety of applications, ranging from medical to industrial, in neutral or harsh environments.

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Bias enhanced nucleation of diamond on silicon (100) in a HFCVD system

Cited by 56 publications

References 15 publications

Control of the in-plane thermal conductivity of ultra-thin nanocrystalline diamond films through the grain and grain boundary properties

Control of the in-plane thermal conductivity of ultra-thin nanocrystalline diamond films through the grain and grain boundary properties

Nanocrystalline diamond microelectrode arrays fabricated on sapphire technology for high-time resolution of quantal catecholamine secretion from chromaffin cells

Fabrication of a NCD microelectrode array for amperometric detection with micrometer spatial resolution

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