Direct deposition of polycrystalline diamond films on Si(100) without surface pretreatment

Abstract

Dense nucleation of small-grain polycrystalline diamond films on Si(100) substrates has been accomplished without the use of any surface pretreatment such as abrasive diamond scratching, surface oil treatments, or diamond-like carbon predeposition. Diamond depositions occurred in a low-pressure rf plasma-assisted chemical vapor deposition system using mixtures of CF4 and H2. Films deposited at 5 Torr and 850 °C on as-received silicon wafers show dense nucleation, well-defined facets, and crystallites which ranged in size from 500 to 10 000 Å. X-ray photoelectron spectroscopy and electron energy loss show the films to be diamond with no major impurity and no detectable graphitic component. Raman spectroscopy shows a pronounced 1332 cm−1 line accompanied with a broad band centered about 1500 cm−1.