Wide variations of SiCxNy:H thin films optical constants deposited by H2/N2/Ar/hexamethyldisilazane microwave plasma

SiCxNy:H thin film growth has been achieved in N2/H2/Ar/hexamethyldisilazane microwave plasma induced chemical vapor deposition process. Depending on the N2 and H2 flow rates, film composition can be changed from “SiCx:H-like” to “SiNx:H-like”. Therefore, refractive index (n) and Taucʹs optical gap (Eg) are modified over a wide range of values (1.75 ≤ n ≤ 2.15 and 3.5 eV ≤ Eg ≤ 5 eV). In addition, n and Eg values are closely related to SiC bonding density. N2 addition to the plasma leads to the substitution of SiC by SiN bonds in the film and results in important composition and optical constants variations. This “silane free” process appears as an interesting plasma induced chemical vapor deposition process for silicon-based coating synthesis in the field of optical applications.