Diamond deposition with sulfur addition-thermodynamic calculations

摘要

The doping of diamond is an interesting topic for the production of microelectronic devices.During the last years the possibility of S-doping was shown and also n-type semiconductivity was described.Analytical measurements in the gas phase and thermodynamic calculations of the stable compounds were also reported,but the results were not always consistent.Thermodynamic calculations were carried out for a wide parameter range e.g.up to high sulfur concentrations,low and high pressures,various temperatures.The stability of various compounds e.g.H_2S,CS,CS_2,S,CVHV was calculated.Thermodynamic calculations showed that H_2S reacts with methane to form the compound CS during filament activation.At the substrate temperature for diamond deposition (< 1000 deg C) there should be the reverse reaction from CS to H2S.Diamond deposition experiments were carried out in a hot-filament apparatus and H_2S was used as a sulfur compound (between 400 and 2200 ppm H_2S/CH_4).The thermodynamic calculations and diamond deposition results were compared with literature data.