INFLUENCE OF ION-BOMBARDMENT ON A-SI-H FILMS FABRICATED BY PLASMA CHEMICAL-VAPOR-DEPOSITION

Plasma parameters of Ar/SiH4 plasma were measured as a function of de bias in a double-tubed coaxial line-type microwave plasma chemical vapor deposition (CVD) apparatus. The results indicate that it is possible to control the ion bombardment energy without affecting either the gas phase reaction or ion flux density incident to the substrate. Hydrogenated amorphous silicon films were deposited as a function of the ion bombardment energy and characteristics of the deposited films were investigated. The results indicate that the ion bombardment improves film density, bonding characteristics of hydrogen, and optical band gap but increases the concentration of dangling bonds due to Ar ion implantation. The ion bombardment not only causes the heating of the films but also induces sputtering and ion implantation.