On forces in microelectromechanical systems

This paper investigates forces of importance in microelectromechanical systems (MEMS), their origin, effective range of action, proper classification, and formulations. It is shown that because of extremely small sizes of micromechanical structures in MEMS, forces operating at surfaces, across interfaces, and between micromechanical components caused by molecular interactions and by electric and magnetic loadings may become significant to influence behaviors of microelectromechanical devices. It is also shown that interaction forces between material bodies can be effectively of much longer range than those between molecules even though the same type of force may be operating in each case, depending on the shape, size, and material properties of the interacting media. Even quantum electrodynamic effects are shown to play effectively roles in MEMS in certain cases. To identify relative importance of forces in MEMS, a comparison of some major operating forces is made quantitatively with respect to their interaction range of interacting media, and its results are discussed in the paper. Possible effects of forces and their applications are also discussed briefly for MEMS in which a variety of forces may play important roles.