INFLUENCE OF THE TEMPERATURE OF MOLYBDENUM SUBSTRATES ON THE STRUCTURE OF DIAMOND COATINGS OBTAINED BY CHEMICAL VAPOR DEPOSITION FROM A HIGH-SPEED MICROWAVE PLASMA JET

We present a study of structural features of diamond coatings prepared by chemical vapor deposition from a hydrogen/methane mixture activated by a microwave discharge using a high-speed jet to transport the mixture to molybdenum substrates heated up to 525 °C, 690 °C, and 1000 °C. The influence of the substrate temperature on morphology, composition, and structure of diamond coatings are studied by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and near edge X-ray absorption fine structure. The diamond crystals enlarge in size, their density on the substrate increases, while the quality and the crystal surface purity are enhanced as a result of temperature increase.