n-Type doping of diamond by hot-filament chemical vapor deposition growth with phosphorus incorporation

Epitaxial growth of n-type semiconductor diamond films on (111)-oriented diamond has been achieved by hot-filament chemical vapor deposition (HFCVD) using a methane source and a trimethylphosphine dopant source. Secondary-ion mass spectrometry showed that the phosphorus atoms are incorporated into the films in the concentration range of 10 18 –10 19 cm −3 from the vapor phase. Hall-effect measurements confirmed n-type conductivity in a wide temperature range up to 873 K. Electrons are thermally activated from a phosphorus donor level of approximately 0.57 eV as dominant carriers under the presence of tungsten atoms with concentrations of around 10 18 cm −3 from filaments. These results indicate that HFCVD has the potential to be applied to an n-type doping process for fabricating diamond electronic devices in the phosphorus concentration range of not lower than 10 18 cm −3 .