A Mems Tribometer for on-Chip Measurements of Dynamic Friction Loops
  A MEMS based tribometer has been developed that can be read out with nanometer and nano-Newton resolution, approaching the resolution and sensitivity of a friction force microscope (FFM). It can be used to study friction of MEMS device sidewall surfaces. We find repeatable but irregular stick-slip behavior related to the surface roughness or surface modification (wear), depending on the normal force between the sliding surfaces. In addition, we show that normal force modulation can decrease the apparent friction even though the average normal force remains the same. This may be a technologically viable way to reduce friction and wear in microscopic contacts. 
Merlijn W.M. Van Spengen, Viviane Turq, Geert G.H.C.J. Wijts, Joost   J.W.M. Frenken