Preparation of amorphous Si1-xCx (0≤x≤1) films by alternate deposition of Si and C thin layers using a dual magnetron sputtering source

Amorphous Si1-xCx (0 less than or equal to x less than or equal to 1) films have been prepared by alternately depositing thin Si and C layers on aluminosilicate glass substrates by magnetron sputtering. The apparatus used in the experiment was a dual-cathode sputtering machine with a carrousel type substrate holder. When a substrate passes in front of the cathode by rotating the substrate holder at a rotation rate of 60 rev./min, a thin Si layer of 0.057 am (d.c. current: 0.2 A) and a thin C layer of 0.028 nm (d.c. current: 0.4 A) were alternately deposited on the substrate, resulting in the preparation of SiC film. The C/Si compositional ratio of films deposited was controlled by changing the discharge power (the flux) of Si and C. The structural, optical and mechanical properties of the deposited films were examined as a function of C concentration (x). Results of X-ray photoelectron spectroscopy showed that the film composition changed from x = 0 to x = 1 with increasing C flux ratio. The peak positions of Si 2p and C 1 s shifted also, showing the formation of Si-C bond in the films. The X-ray diffraction measurements showed that films deposited were amorphous for all the composition. The maximum hardness of approximately 30 GPa was obtained for a film deposited at xapproximate to0.5 by a nanoindentation. This value was almost equal to that of a SiC film deposited by conventional r.f. sputtering of SiC. Internal stresses of films ranged from -0.5 to -1.0 GPa (compressive) and were 1/2-1/4 compared to that of the SiC film deposited from a by a conventional sputtering of SiC without rotating substrate. (C) 2002 Elsevier Science B.V. All rights reserved.