Carbon Nanotube-based Nems Switch Design, Simulation And Process Research

As the extension and development of MEMS, Nano-electromechanical systems (NEMS) is drawing more and more attention because of the unprecedented and intriguing properties in the fields of sensing and electronic computing. NEMS based devices can have an extremely high fundamental mechanical oscillation frequency, while preserving a robust mechanical response. Carbon nanotubes (CNTs) are ideal materials for NEMS devices due to their superior electromechanical properties, such as low masses, low density, high intensity and high natural frequency. Nanotube based nanoswitch will have superior properties which MEMS switch don't have.In this paper a multiphysics simulation of nanotube based nano-electromechanical systems is reported. Assuming continuum mechanics, the nonlinear deformation of the nanotube is simulated using finite element method. We try three simulation methods in ANSYS and do some comparison. They are based on MFS, ROM144 and TRANS126 separately. The simulation emphasizes the behavior of singly and doubly clamped nanotubes under electrostatic actuation and the prediction of the pull-in voltage of the nanoswitch, a key design parameter. Moreover, the nonlinear behavior associated with finite kinematics (i.e., large deformations), neglected in previous studies, are investigated in detail. The multiphysics simulation results agree well with the theoretical predictions verifying that the numerical model is valid. The results show that nonlinear kinematics results in an important increase in the pull-in voltage of doubly clamped nanotube devices, but that it is negligible in the case of singly clamped devices. These models provide a guide on the effect of the various geometrical variables as well as materials and insight into the design of novel devices.