Atomic force microscopy and X-ray photoelectron spectroscopy evaluation of adhesion and nanostructure of thin Cr films

Abstract

Chromium (Cr) thin films were deposited on float glass using electron beam (e-beam) physical vapor deposition and radio frequency (RF) magnetron sputtering techniques. Surface morphology of these Cr films was studied using atomic force microscopy (AFM). The e-beam deposited Cr films consisted of isolated surface mounds while in RF sputtered samples, these mounds combined to form larger islands. Lower surface adhesive properties were observed for e-beam deposited films, as determined from AFM force–distance curves, presumably due to the nanostructural differences. Similar amounts of adsorbed atmospheric carbonaceous contaminants and water vapor were detected on samples deposited using both methods with e-beam deposited samples having additional carbide species, as determined by X-ray photoelectron spectroscopy data. The dominant crystallographic plane in both e-beam deposited and RF sputtered Cr thin films was (110) of body-centered cubic Cr metal structure as determined from X-ray diffraction data. Weak (211) reflection was also observed in RF sputtered samples and was attributed to a different thin Cr film condensation and growth mechanism which resulted in nanostructural differences between films deposited using two different methods.