Defined etching of carbon-diamond films on silicon using an oxygen plasma with titanium masking

A technique for pattern transfer onto carbon-diamond films deposited by radio-frequency plasma-enhanced chemical vapour deposition is reported. Such a technique involves standard photolithography processes and reactive ion etching by oxygen and is compatible with present day microelectronic technology. The patterns transferred are well defined with very good resolution. © 1992.

Encapsluation of Co and Pd multi-metal nanowires inside multiwalled carbon nanotubes by microwave plasma chemical vapor deposition

We report the synthesis of multiwalled carbon nanotubes (MWCNTs) encapsulated with Co/Pd magnetic and nonmagnetic multi-metal nanowires using Co and Pd thin-layers deposited on Si substrate by microwave plasma enhanced chemical vapor deposition using a bias-enhanced growth method. Detailed structural and compositional investigations of these metal nanowires inside MWCNTs were carried out by scanning electron microscopy and transmission electron microscopy to elucidate the growth mechanisms. Energy dispersive X-ray spectroscopy revealed that MWCNTs were encapsulated with Co and Pd nanowires, separately, at the tube top and the bottom of Co nanowire, respectively. The face-centered-cubic (fcc) structure of Co nanowires was confirmed by a selected area diffraction pattern. We proposed a fruitful description for the encapsulating mechanisms of both Co and Pd multi-metal nanowires. © 2006 Elsevier B.V. All rights reserved.

Optical emission spectroscopy of the plasma during sputter deposition of YBCO films for microwave applications

YBCO thin films are currently used in several HTS-based electronics applications. The performance of devices, which may include microwave passive components (filters, resonators), grain boundary junctions or spintronic multilayer structures, is determined by film quality, which in turn depends on the deposition technology used and growth parameters. We report on results from nonintrusive Optical Emission Spectroscopy of the plasma during YBCO thin film deposition in a high-pressure on-axis sputtering system under different conditions, including small trace gas additions to the sputtering gas. We correlate these results with the compositional and structural changes which affect the DC and microwave properties of YBCO films. Film morphology, composition, structure and in- and out-of-plane orientation were assessed; T, and microwave surface resistance measurements were made using inductive and resonator techniques. Comparison was made with films sputtered in an off-axis 2-opposing magnetron system.

Cell adhesion to plasma electrolytic oxidation (PEO) titania coatings, assessed using a centrifuging technique.

The adhesion of bovine chondrocytes and human osteoblasts to three titania-based coatings, formed by plasma electrolytic oxidation (PEO), was compared to that on uncoated Ti-6Al-4V substrates, and some comparisons were also made with plasma sprayed hydroxyapatite (HA) coatings. This was done using a centrifuge, with accelerations of up to 160,000 g, so as to induce buoyancy forces that created normal or shear stresses at the interface. It is shown that, on all surfaces, it was easier to remove cells under normal loading than under shear loading. Cell adhesion to the PEO coatings was stronger than that on Ti-6Al-4V and similar to that on HA. Cell proliferation rates were relatively high on one of the PEO coatings, which was virtually free of aluminium, but low on the other two, which contained significant levels of aluminium. It is concluded that the Al-free PEO coating offers promise for application to prosthetic implants.

Plasma enhancement of current from carbon cathodes for field emission displays

This paper examines the possibility of using a background gas medium to enhance the current available from low threshold carbon cathodes. The field emission current is used to initiate a plasma in the gas medium, and thereby achieve a current multiplication effect. Results on the variation of anode current as a function of electric field and gas pressure are presented. These are compared with model calculations to verify the principles of operation. The influence of ion bombardment on the long term performance thin film carbon cathodes is examined for He and Ar multiplication plasmas. A measure of the influence of current multiplication on display quality is presented by examining light output from two standard low voltage phosphors. Also studied are the influence of doping the carbon with N to lower the threshold voltage for emission as well as the consequent impact on anode current from the plasma.