Effects of hydrogen and rf power on the structural and electrical properties of rf sputtered hydrogenated amorphous silicon carbide films

Abstract

The effects of the rf power (100 to 600 W) and the hydrogen partial pressure (PH=0.15 to 0.6 Pa.) on the deposition rate and the structural and electrical properties of rf sputtered hydrogenated amorphous silicon carbide (a-Si1-xCx :H) films were investigated. The films were deposited in an argon plus hydrogen ambient. The deposition rate increased with increasing rf power, but decreased with increasing PH. The refractive index increases from 1.85-3.6 as the rf power increases from 100-600 W and from 2.8 to 3.5 as PH increases from 0.15-0.6 Pa. The optical gap increases from 1.5 to 2.15 eV as PH increases from 0.15-0.6 Pa, but decreases from 2.8-1.38 eV as the rf power increases from 100-600 W. The Si-C bond gave the most prominent absorption peak in the infrared spectra, and increased with increasing rf power but not affected by changes in PH. The Si-H bonds increases from 3.06×1021 to 1.64×1022 cm-3 as PH was increased from 0.15-0.6 Pa. The optical gap increases from 1.5-2.15 eV and the conductivity reduces from 7.3×10-9 to 1.9×10-11 Ω-1 cm-1 accordingly. No C-Hn stretching mode was detected in all the films and this was attributed to the low carbon content of the films. We conclude that rf sputtering technique is not effective in varying the carbon content in a-Si1-xCx:H films. © 1996 American Institute of Physics.