Defining the Role of Silicon Substrate Orientation on the Polycrystalline Diamond Film: A Novel Approach for Characterizing Faceted Microstructures

Abstract

Polycrystalline diamond films (∼10 μm thick) were grown on five different silicon (Si) substrate orientations by microwave plasma chemical vapor deposition. The selected Si substrates had a range of f(θ): 0.18–0.65. It is to be noted that f(θ) scales inversely with the packing density of the interface. As f(θ) decreased, three changes in the polycrystalline diamond microstructures were observed. (i) At the film surface -fiber texture increased but -fiber dropped. (ii) A novel reconstruction technique was proposed and tested for faceted microstructures. The reconstructed microstructures revealed that the observed texture changes, with a decrease in f(θ), was accompanied by elimination of very fine facets. (iii) Noticeable differences in Raman estimated stress gradients were also observed: the lowest stress gradients for more closed packed substrates.