RF-PECVD deposition and optical properties of hydrogenated amorphous silicon carbide thin films

Abstract Hydrogenated amorphous silicon carbide (a-SiC x :H) thin films were deposited using a radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) system with methane (CH 4 ) and silane (SiH 4 ) as reactive precursor gases and H 2 as a carrier and dilution gas. The effects of RF-PECVD deposition conditions on the optical properties and microstructural characteristics of a-SiC x :H thin films were systematically investigated. When the RF power density, deposition pressure ( P ) and temperature ( T s ) were fixed, the refractive index ( n ) and the growth rate of a-SiC x :H thin films decreased with the CH 4 /SiH 4 flow rate ratio ( R ), while their optical band gap ( E g ) increased with R . The a-SiC x :H thin film grown at higher R was found to be smoother than that grown at lower R . When the RF power density, P and R were fixed, the growth rate of a-SiC x :H thin films decreased with T s , while their n increased with T s . It was found that E g slightly increased with T s , and the film became rough at higher T s . When T s , P and R were fixed, the growth rate of a-SiC x :H thin films increased with the RF power density, while their n only slightly increased and E g slightly decreased with the RF power density. It was found that the RF power density had a large impact on the roughness of a-SiC x :H thin films.