19 research outputs found
Modelling of the gas-phase chemistry in C-H-O gas mixtures for diamond chemical vapour deposition
Observations of nanotube and 'celery' structures following diamond CVD on single crystal diamond substrates
Low temperature diamond growth using CO<sub>2</sub>/CH<sub>4</sub> plasmas: molecular beam mass spectrometry and computer simulation investigations
<i>In situ</i> plasma diagnostics of the chemistry behind sulfur doping of CVD diamond films
Molecular beam mass spectrometry investigations of low temperature diamond growth using CO<sub>2</sub>/CH<sub>4</sub> plasmas
Sulfur addition to microwave activated CH<sub>4</sub>/CO<sub>2</sub> gas mixtures used for diamond CVD:Growth studies and gas phase investigations
Microwave plasma chemical vapour deposition (MPCVD) has been used to deposit diamond films with H2S additions of 0–5000 ppm to a 51 % CH4/49 % CO2 plasma, with growth carried out for two different substrate temperatures (620 and 900 C). Film morphology, growth rate and quality are all observed to deteriorate with increased H2S addition, as investigated by scanning electron microscopy (SEM) and laser Raman spectroscopy (LRS). H2S addition also appears to alter the resistivity of films, as measured by the four-point probe method, however X-ray photoelectron spectroscopy (XPS) revealed little incorporation of sulfur. The plasma chemistry leading to film deposition has been investigated using optical emission spectroscopy (OES), in which H2S addition leads to a reduction in C2 * and CH * intensities. Molecular beam mass spectrometry (MBMS) measurements have detected a build-up in CS, CS2, SO and SO2 concentrations with addition of H2S. Experimental results have been compared to CHEMKIN simulations of plasma chemistry and S-incorporation has been investigated in terms of the product of CHEMKIN predicted mole fractions of CH3 and CS, [CH3] [CS]. I