Adhesive Force in Micro- and Nano-System

One of the most important reliability problems in micro- and nano-systems is stiction, the adhesion between micro-devices due to surface forces. Although several different physical theories had been put forward to investigate the adhesion problems in micro- and nano-systems, none of them can give a continuous variation of the adhesive force with the distance (if the micro-devices contact, the distance is the negative compressive deformation) between micro-devices. After reviewing the known physical theories, three combined adhesive models are developed to provide a continuous variation of the adhesive force with the distance. This is done by rectifying the coefficients and definition domains of the adhesive theories available based on the maximal stretch deformation of elastic bodies given by them after a parameter of critical contact distance is introduced to the current adhesive theories. A comparison between a widely used numerical method and the combined adhesive models shows that the combined adhesive models established in this article are valid in investigating the adhesive force in micro- and nano-systems.