Naoki Oyanagi

The synthesis of diamond particles by a filament assisted CO2 laser induced CVD

Abstract Diamond particles were synthesized by a filament assisted CO 2 laser induced CVD technique on a silicon substrate in a hydrogen environment. The deposition was carried out using a gaseous mixture of CH 4 and H 2 , which flowed through a beam generator equipped with a tiny orifice and positioned above a refractory filament. The filament was separated 25 mm from the substrate and a cw-CO 2 laser was used to irradiate the substrates surface. The presence of diamond particles on the substrate was confirmed by Raman Spectroscopy and Scanning Electron Microscope. The factors that hindered the synthesis of a continuous diamond film were investigated from the results of EDS, TEM analysis, HREM analysis, and Electron Diffraction Patterns.

Laser ablation doping process for the synthesis of conductive diamond thin film

Basic to the understanding of the electrical properties of diamond films is the achievement of the synthesis of doped films through specific doping processes. We report a novel laser ablation process for doping diamond thin films. Boron doped diamond thin films were synthesized by the activated beam deposition process with H2/C2H4 gaseous mixtures, and the simultaneous irradiation of a solid boron target with a CO2 laser beam. The presence of boron in the film was confirmed by SIMS analysis. The electrical characteristics of the boron doped films were ascertained by resistivity, carrier concentration and Hall mobility measurements. Raman spectroscopy and SEM micrographs confirmed the quality and crystallinity of the films. Conductivity dependence on temperature was measured between a temperature range of 303 K and 873 K, and the possibility of the application of the process to synthesize alternative layers of insulating and conducting films was demonstrated.