Study of Evolution of Surface Roughness of Cu Thin Films

Abstract

Thin film technology is the foundation of wondrous technological advances made in the fields of optoelectronic, photonic, magnetic and solid state electronic devices. Surface morphology of deposited thin films and the method used in depositing thin films are of great interest. The surface roughness plays a critical role in many applications and properties such as contact mechanics, sealing, friction, adhesion, optics and electrical conductivity. The Dynamic Scaling Theory was used to study the surface roughness and scaling behavior of Cu thin films grown on glass substrate by DC magnetron sputtering at 75W power at varying time. The phase of resulting thin films was characterized by X-ray diffraction (XRD), and growth of surface with increasing time was studied by using Atomic Force Microscopy. Determination of the PSDF (Power Spectral Density Function) and HHCF (Height-Height Correlation Function) of the films deposited for different times were used to evaluate details of the kinetic roughening. From the measured exponents, in conjunction with the computed ones, determination of the growth mechanisms were carried out and the processes was classified within certain universality classes. Detailed scaling analysis of surface fluctuation in real and fourier space yielded characteristic exponents indicate the presence of super-roughening on the line of anomalous scaling and not the conventional scaling obeying Family–Vicsek equation.