Synthesis and electrical properties of phosphorus-doped homoepitaxial diamond (111) by microwave plasma-assisted chemical vapor deposition using triethylphosphine as a dopant source

A phosphorus-doped (Ill)diamond film was formed homoepitaxially on a nondoped diamond film, which was also formed homoepitaxially on a type Ib (111) diamond substrate, by microwave plasma-assisted chemical vapor deposition using CH4 as the carbon source and triethylphosphine (TEP, P(C2H5)(3)) as the dopant source. The P-doped film, which was approximately 800 nm in thickness, exhibited an n-type conduction in the temperature range of 100-500 K. This represents the first such observation, for a film prepared using TEP as the dopant. The activation energy for carrier concentration was 0.09 eV in the range of 145-500 K. The Hall mobility reached a maximum of approximately 3.5 cm(2)/(Vs) at 145 K and decreased to 0.15 cm(2)/CVs) at 500 K. Phosphorus was uniformly incorporated into the diamond film, as evidenced by secondary ion mass spectrometry.