Low-temperature deposition of diamond films for optical coatings

Abstract

A low-temperature (≊400 °C) plasma-enhanced chemical vapor deposition process has been developed to grow diamond films for optical coatings application. Films with fine grains (≤3000 Å) have been obtained by controlling diamond nucleation. The surface roughness of the films is on the order of 50–200 Å. The optical transparency of the films is over 60% in the range 0.6–2 μm wavelength, which is comparable to that of Type IIa natural diamond. Using a block-on ring tribotester, it is found that the diamond films adhere well to quartz substrates.