Effect of hydrogen on the properties of magnetron sputtering of hydrogenated amorphous silicon carbon alloy films

Abstract

Hydrogenated amorphous silicon carbon alloy films have been prepared by magnetron sputtering of silicon in methane-hydrogen-argon gas mixtures, and the dependence of film properties on hydrogen partial pressure (PH) as well as methane partial pressure against total gas pressure has been investigated. With increasing PH, the concentration of carbon increases, accompanied with the increase in the number of Si–C bonds, in spite of the unchanging partial pressure of methane. Following this, the optical band gap and activation energies of dc conductivities increase, and the photoconductivity as well as the dark conductivity decreases. The intensity of Si–H bonds is almost unchanged, while that of C–H bonds increases. These results are discussed mainly from the standpoint of the change of deposition process composed of the chemical decomposition of methane and the physical sputtering of silicon.