Monitoring of the Initial Stages of Diamond Growth on Aluminum Nitride Using In Situ Spectroscopic Ellipsometry.

The high thermal conductivity of polycrystalline diamond makes it ideally suited for thermal management solutions for gallium nitride (GaN) devices, with a diamond layer grown on an aluminum nitride (AlN) interlayer atop the GaN stack. However, this application is limited by the thermal barrier at the interface between diamond and substrate, which has been associated with the transition region formed in the initial phases of growth. In this work, in situ spectroscopic ellipsometry (SE) is employed to monitor early-stage microwave plasma-enhanced chemical vapor deposition diamond growth on AlN.

Polycrystalline Diamond Micro-Hotplates.

Micro-hotplate structures are increasingly being investigated for use in a host of applications ranging from broadband infra-red sources within absorption-based gas sensors to in situ heater stages for ultra-high-resolution imaging. With devices usually fabricated from a conductive electrode placed on top of a freestanding radiator element, coefficient of thermal expansion (CTE) mismatches between layers and electro-migration within the heating element typically lead to failure upon exceeding temperatures of 1600 K. In an attempt to mitigate such issues, a series of hotplates of varying geometry have been fabricated from a single layer of mechanically robust, high thermal conductivity, and low CTE boron-doped polycrystalline diamond.

Electropositive Nanodiamond-Coated Quartz Microfiber Membranes for Virus and Dye Filtration.

Electropositive membranes demonstrating high flux at low pressure differentials show great promise as universal separation platforms for viruses and other charged entities when centralized systems of water and power are scarce. However, the fabrication of a suitably stable membrane with optimal electrostatic characteristics remains a challenge. Here, hydrogenated detonation nanodiamond was loaded onto a quartz microfiber support membrane and coupled to the membrane surface under a high vacuum annealing process.

Author Correction: Superconducting Diamond on Silicon Nitride for Device Applications.

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Superconducting Diamond on Silicon Nitride for Device Applications.

Chemical vapour deposition (CVD) grown nanocrystalline diamond is an attractive material for the fabrication of devices. For some device architectures, optimisation of its growth on silicon nitride is essential. Here, the effects of three pre-growth surface treatments, often employed as cleaning methods, were investigated.

Air-clad suspended nanocrystalline diamond ridge waveguides.

A hybrid group IV ridge waveguide platform is demonstrated, with potential application across the optical spectrum from ultraviolet to the far infrared wavelengths. The waveguides are fabricated by partial etching of sub-micron ridges in a nanocrystalline diamond thin film grown on top of a silicon wafer. To create vertical confinement, the diamond film is locally undercut by exposing the chip to an isotropic fluorine plasma etch via etch holes surrounding the waveguides, resulting in a mechanically stable suspended air-clad waveguide platform.

Microwave Permittivity of Trace sp Carbon Impurities in Sub-Micron Diamond Powders.

Microwave dielectric loss tangent measurements are demonstrated as a method for quantifying trace sp-hybridized carbon impurities in sub-micron diamond powders. Appropriate test samples are prepared by vacuum annealing at temperatures from 600 to 1200 °C to vary the sp/sp carbon ratio through partial surface graphitization. Microwave permittivity measurements are compared with those obtained using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electron energy loss spectroscopy (EELS).

Effect of slurry composition on the chemical mechanical polishing of thin diamond films.

Nanocrystalline diamond (NCD) thin films grown by chemical vapour deposition have an intrinsic surface roughness, which hinders the development and performance of the films' various applications. Traditional methods of diamond polishing are not effective on NCD thin films. Films either shatter due to the combination of wafer bow and high mechanical pressures or produce uneven surfaces, which has led to the adaptation of the chemical mechanical polishing (CMP) technique for NCD films.

Spectroscopic Ellipsometry of Nanocrystalline Diamond Film Growth.

With the retention of many of the unrivaled properties of bulk diamond but in thin-film form, nanocrystalline diamond (NCD) has applications ranging from micro-/nano-electromechanical systems to tribological coatings. However, with Young's modulus, transparency, and thermal conductivity of films all dependent on the grain size and nondiamond content, compositional and structural analysis of the initial stages of diamond growth is required to optimize growth. Spectroscopic ellipsometry (SE) has therefore been applied to the characterization of 25-75 nm thick NCD samples atop nanodiamond-seeded silicon with a clear distinction between the nucleation and bulk growth regimes discernable.

Chemical Nucleation of Diamond Films.

With the large differences in surface energy between film and substrate in combination with the low sticking coefficient of hydrocarbon radicals, nanocrystalline diamond growth on foreign substrates typically results in poor nucleation densities. A seeding technique is therefore required to realize pinhole-free and thin coalesced films. In this work, a chemical nucleation method for growth of diamond on nondiamond substrates based on 2,2-divinyladamantane is shown.