White diamond films, which should be composed of almost pure diamond grains, have been successfully obtained at high pressure (above 150 Torr) by microwave-plasma-enhanced chemical vapour deposition. The characteristics of the films have been examined using scanning electron microscopy and Raman spectroscopy. As the total pressure and microwave power increase, the film quality is enhanced and the film morphology changes. The film quality is found to be closely associated with the variation in the gas components in the plasma. The variation in the surface morphology of the films with total pressure is related to the substrate temperature. Transmission electron microscopy results reveal that an alpha-SiC interface layer forms prior to the growth of the diamond films at 60 Torr.