Annealing effects on SiOxNy thin films: Optical and morphological properties

The annealing effect on the properties of silicon oxynitride (SiOxNy) thin films has been investigated. The present contribution aims to study the structural and optical properties of SiOxNy thin films deposited by plasma enhanced chemical vapor deposition in view of their application in the field of photovoltaics. Evolution of the surface morphology and increase of the optical band gap with the thermal treatment have been determined and discussed in view of the application of the film as an emitter layer in heterojunction solar cells. •SiOxNy deposited by plasma enhanced chemical vapor deposition.•Increase of lateral correlation length and grain size upon annealing•Atomic force microscopy employed for investigation of the surface evolution.•Increase of the optical Tauc gap upon annealing, high values achieved.•Reflection and transmission spectra employed for Tauc gap determination.