CAPACITY COUPLED RF DISCHARGE PLASMA-JET TREATMENT OF A-SIC-H STRUCTURES

Amorphous hydrogenated silicon carbide (a-SiC:H) thin films were treat ed in a capacity coupled r.f. discharge plasma jet working in nitrogen . The samples, with a carbon content in the range of 30%-50%, were dep osited onto Si(100) wafers by plasma enhanced chemical vapor depositio n. The capacity coupled r.f. discharge (less than 100 W) is generated in flowing nitrogen or ammonia in a small distance (1-2 mm) gap, at me dium pressure (3-25 torr). The gap is limited by a planar (40 mm diame ter) electrode and a nozzle (1-2 mm) opening. Plasma expands as a brig ht nitrogen plasma jet in a larger vacuumed vessel. The sample's holde r (which can be heated) was placed downstream the nozzle at several ce ntimeters distance, being exposed to the plasma beam. In this way the samples (a-SiC:H) were irradiated. Various techniques, such as X-ray d iffraction, X-ray photoelectron spectroscopy, Fourier infrared transmi ssion spectroscopy measurements, spectroscopic ellipsometry and microh ardness measurements were used to characterize the induced composition evolution towards Si-C-N (SiC-SiN-CN) mixtures.