Surface wet-ability modification of thin PECVD silicon nitride layers by 40keV argon ion treatments

Measurements of wet-ability of liquid drops have been performed on a 30nm silicon nitride (Si3N4) film deposited by a PECVD reactor on a silicon wafer and implanted by 40keV argon ions at different doses. Surface treatments by using Ar ion beams have been employed to modify the wet-ability. The chemical composition of the first Si3N4 monolayer was investigated by means of X-ray Photoelectron Spectroscopy (XPS). The surface morphology was tested by Atomic Force Microscopy (AFM). Results put in evidence the best implantation conditions for silicon nitride to increase or to reduce the wet-ability of the biological liquid. This permits to improve the biocompatibility and functionality of Si3N4. In particular experimental results show that argon ion bombardment increases the contact angle, enhances the oxygen content and increases the surface roughness.