INTERMEDIATE LAYERS FOR THE DEPOSITION OF POLYCRYSTALLINE DIAMOND FILMS

Thin films of BN, hard carbon, α-C:H, and SiC have been deposited onto ZnS or (100) silicon as precursors to the growth of polycrystalline diamond films. These layers most protect the substrate from chemical attack at the deposition temperatures used in microwave plasma chemical vapor deposition (CVD) and also promote the nucleation of crystalline diamond. The thermal stability, the optical properties of these coatings, and their ability to nucleate diamond growth are investigated. BN thin films appear to be the best interlayer for both protection and nucleation enhancement. Hard carbon and α-C:M interlayers provide no real benefit in themselves. Silicon carbide was identified at the interface between one type of hard carbon film and the silicon substrate using x-ray photoelectron spectroscopy (XPS). Si C islands may provide nucleation sites for CVD diamond. Silicon carbide can provide both protection and nucleation enhancement if the crystallinity and texture are optimized. © 1990, American Vacuum Society. All rights reserved.