Tribological properties of nanoscale GeSb2Te4 film in the ambient air

In this paper, lateral force microscope (LFM) is used to investigate the frictional behavior of GeSb2Te4 film of 20 nm thickness deposited by magnetron sputtering. The effect of relative humidity, scanning rate, scanning area on friction is concerned. The JKRS (Johnson–Kendall–Roberts) theory considering the energy of adhesion between tip and GeSb2Te4 (at.%) film is introduced. Experimental results indicate that high humidity leads to high adhesive force, low humidity to low adhesion. When the tip's surface energy is unchanged, minute change of surface energy of GeSb2Te4 film will affect the adhesive force. Experiment also shows that variance of friction level goes unanimous at the different scanning area and the same normal load. Next, the effect of scanning rate on friction is attributed to the surface absorbate and liquid film. Finally, it suggests that relative humidity and protective coating should be considered for the promising ultra-high density probe storage medium.