Growth of in situ multilayer diamond films by varying substrate-filament distance in hot-filament chemical vapor deposition

Single and multilayer diamond films were grown on silicon by varying substrate distance in hot-filament chemical vapor deposition. The grown films were characterized by scanning electron microscope (SEM) and Raman spectroscopy. From SEM surface images, it was observed that the films grown at substrate distances of 8, 7, and 6 mm and temperatures of 740, 780, and 830 degrees C possessed cauliflower, pseudocubes, and finally well-faceted cubes morphology. SEM fracture cross-sectional investigations revealed that growth of pseudocubes initiated on the top of cauliflower structure. By using the parametric relations gathered from single layer diamond growth studies, first time, multilayer diamond coatings were grown in situ with tunable thickness by only varying the substrate distance from filament assembly during deposition.