Hydrogenated Silicon Carbonitride Thin Film Nanostructuring Using SF6 Plasma: Structural and Optical Analysis

Hydrogenated silicon carbonitride thin films have been deposited on silicon substrates in a plasma enhanced chemical vapor deposition (PECVD) system using hexamethyldisilazane (HMDSN: C6H19Si2N) as an organosilicon monomer precursor, the plasma polymerized HMDSN (pp-HMDSN) films surfaces have been subsequently nanostructured via SF6 plasma surface etching for different etching times of 0.5 min, 1 min and 3 min. The plasma etching of pp-HMDSN thin film surface affected its surface morphology, chemical structure, wettability property, optical anti-reflectance characteristics and photoluminescence (PL) emission property. It is found that with etching time increase, the refractive index decreases and the PL energy bandgap increases as the silicon content and chemical bond Si-C intensity in thin film decrease, the optical reflectance spectrum changed in shape and position of minimum reflectance and the surface is converted from hydrophilic to hydrophobic one as surface porosity is enhanced.