Introduction
Titanium (Ti), due to high mechanical strength, excellent
thermal stability, good corrosion resistance and intrinsic biocompatibility
has received a great deal of attention over the last three
decades. These features make it very useful, not only for
mechanical applications, but also for the aerospace, medical and
microelectronics industries [1–3]. For these applications, smooth
surface, fine grain and homogenous structure of Ti thin films are of
critical importance.
Many studies on magnetron sputtered Ti thin films have been
reported [4–7]. For example, Jeyachandran et al. [4] investigated
the effect of thickness on the electrical, structural, optical and
surface properties of sputtered Ti films. Godfroid et al. [5] have
studied the influence of sputtering current on the growth modes of
sputtered Ti films. Chemical composition and structural properties
of Ti thin films sputtered under various cathode power, sputtering
pressure and base vacuum conditions have also been investigated
[6]. Martin et al. [7] have researched the influence of bias power on
some properties of Ti coatings. However, these studies do not deal
with a systematic investigation on morphological evolution of Ti
films on the nanometer scale with respect to the deposition
parameters. Undoubtedly, it is very important for the nanometerscale
characterization of surface topography of thin films to obtain
smooth surface, fine grain and homogenous structure [8].
The goal of this work was to investigate sputtering power
affecting surface topography of direct current (dc) magnetron
sputtered Ti films on the nanometer scale using atomic force
microscopy (AFM). Since the invention of AFM in 1986 [9], it has
became a very popular and effective method to measure surface
topography of thin films. An important advantage compared with
electron beam methods is that AFM can operate in ambient
environments. Obviously, AFM technology has widely been used in
the measurement of the hyperfine surface topography of thin solid
films