Valence band photoelectron spectroscopy and structural morphology of nitrogen- and boron-containing MPACVD diamond films

Abstract

Diamond thin films with various concentrations of nitrogen and boron were prepared by microwave-assisted chemical vapour deposition in a standard downstream microwave system. For the nitrogen-containing films, nitrogen was added to the feed gas, while the boron-containing films were produced by placing a piece of boron carbide (B 4C) in the plasma. The films were characterized by photoelectron spectroscopy and scanning electron microscopy (SEM). One boron-containing sample has been examined by secondary ion mass spectrometry and a homogeneous boron concentration depth profile throughout the diamond film has been observed. SEM images show that nitrogen in the feed gas induces a more ballas-like crystal structure, whereas boron incorporation has only a small influence on the crystal size and structure in the films. For these films the valence band structure is measured by UV photoelectron spectroscopy. Raman spectroscopy has been used in order to characterize the film quality.