SILICON CONTAMINATION OF DIAMOND FILMS DEPOSITED ON SILICON SUBSTRATES IN FUSED-SILICA BASED REACTORS

Deposition of thin diamond films on silicon (Si) substrates and in a r eactor with fused silica walls can lead to the incorporation of Si imp urities. In the present work, impurities in the bulk of the films were analyzed quantitatively using complementary diagnostic techniques (el astic recoil detection, electron microprobe analysis and secondary ion mass spectrometry), while surface analysis was achieved with x-ray ph otoelectron spectroscopy. The Si contamination level in the bulk reach es up to 0.16 at. %. We show that the presence of Si impurities correl ates with the fluorescence background that accompanies the 1332 cm(-1) diamond peak in the Raman spectra. Experiments were performed to dist inguish between the Si originating from the wall and from the Si subst rate. The effect of O-2 added to the process gases is also investigate d. The diamond films were prepared in a recently developed plasma reac tor using a novel configuration of surface-wave-sustained discharge: t he reactor operation is akin to that of the well-known plasma-ball sys tems. (C) 1996 American Institute of Physics.