Structural and optical properties o plasma-deposited a-C:H:Si:O:N films

Thin a-C:H: Si:O:N films were deposited from plasmas fed hexamethyldisiloxane, oxygen and nitrogen, and characterized as a function of the partial pressure of oxygen in the feed, R-ox. Deposition rates varied from 10 to 27 nm min(-1). Surface roughness was independent of R-ox, being around 10 nm. The films contain C=C and C=O, and also Si-C and Si-O-Si groups. Lower [C] and [N] but greater [O] and [Si] were measured in the films as R-ox. was increased. Refractive indices of similar to 1.5 and optical energy gaps which fell from similar to 3.3 to similar to 2.3 eV were observed with increasing R-ox. The Urbach energy fell with increasing optical gap, which is characteristic of amorphous materials. Such materials have potential as transparent barrier coatings.

Automated summary

Thin a-C:H:Si:O:N films were deposited using plasma containing hexamethyldisiloxane, oxygen, and nitrogen at varying oxygen partial pressure. The deposition rates ranged from 10 to 27 nm min(-1). The films exhibited a surface roughness of around 10 nm and contained characteristic groups such as C=C, C=O, Si-C, and Si-O-Si. As the oxygen partial pressure increased, the films showed lower carbon and nitrogen content but higher oxygen and silicon content. The films had refractive indices around 1.5 and optical energy gaps that decreased from around 3.3 to 2.3 eV with increasing oxygen partial pressure. The Urbach energy decreased with increasing optical gap, indicating the characteristic of amorphous materials, and suggesting their potential as transparent barrier coatings.