Optical and mechanical characterization of ultrananocrystalline diamond films prepared in dual frequency discharges
|Type:||Article in Periodical|
|Keywords:||ultrananocrystalline diamond; bias enhanced nucleation; indentation hardness; ellipsometry; FTIR|
Ultrananocrystalline diamond (UNCD) films were deposited directly on polished c-Si substrates in microwave discharge (2.45 GHz) combined with rf capacitive plasma (13.56 MHz) ignited at the substrate electrode. The rf discharge induced a dc self-bias accelerating ions towards the growing film during the whole deposition process. The substrate was either preheated in hydrogen discharge to the deposition temperature of 900 C or the deposition of intermediate layer started at about 200 C and reached 900 C in the 5th minute. The latter procedure resulted in the deposition of coating with the hardness of 70 GPa and very good fracture toughness. The analysis of optical measurement in UV-IR range confirmed the presence of 250 nm thick intermediate layer containing DLC and SiC materials.