Characterization of amorphousSiO2surfaces after biasing pretreatments, which induce nucleation of diamond, has been carried out using x-ray photoelectron spectroscopy and Raman spectroscopy. A mixture of silicon carbide, silicon oxycarbide, and diamond are formed upon exposure of biasedSiO2surfaces to aCH4+H2plasma used for diamond deposition. It is concluded that nucleation of diamond on amorphousSiO2surfaces is promoted by formation of a SiC surface layer. Textured diamond films have been fabricated on bulkSiO2substrates using biasing pretreatments to induce diamond nucleation. ©1997 American Institute of Physics.