Formation of self-assembled platinum particles on diamond and their embedding in diamond by microwave plasma chemical vapor depositions

Single-crystalline and polycrystalline diamond films containing platinum particles with sizes of ≤ ≈ 100 nm have been formed through a self-assembling process. Pt thin films pre-deposited on diamond were found to completely change in shape to grains during a subsequent diamond overgrowth process using a microwave-plasma chemical-vapor-deposition (MPCVD) technique. The self-assembled Pt grains on flat diamond surfaces had approximately spherical particles with rather uniform sizes when the pre-deposited Pt films were sufficiently thin or less than ≈ 1 μm in thickness. The average diameter of such Pt particles, D, was well controlled simply by changing the thickness of the pre-deposited Pt film, tpt, since D was proportional to tpt. Such spherical Pt particles were completely embedded after sufficient diamond overgrowth. Transmission electron microscope observations revealed that most of the spherical Pt particles were well crystallized and that the interfacial structures between the diamond overlayer and the buried Pt particles were sufficiently sharp without any appreciable mixing regions.