Non-Linearity Research On Nano-Oscillation And Molecular Dynamics Simulation On Young Modulus Of Silicon Nano-Beam

As the MEMS processing develops continually, the MEMS devices scale into sub-micrometers even nanometers, which already has become the truth, so that here begins the whole fresh research on NEMS. However, unlike the NEMS processing which basis on the one of MEMS, the theory here for analyzing dynamics of NEMS devices, cannot inherit the MEMS classical theory. Both the smaller dimension and the more ratio of surface to volume, bring the great challenges in this the NEMS area.Research shows that it is comparatively easier to stimulate the transverse oscillation of nano-beam into nonlinear status with the external electromagnetic force because of the reducing of the device scale, and at this situation the classical liner theory is unavailable. The conventional nonlinear model-Duffing model, has low precision without the accurate model parameters which are just obtained form the experiments. This papers provides the physical nonlinear model for the transversal oscillation of nano-beams with the basis of elastic theory and material theory. The whole model considers the axial nonlinear elongation induced by the transversal bend of nano-beam and analyses the nonlinearity. The results show great consistent with the experiments.The further researches indicate that as the devices scale into nanometers, the ratio of surface to volume becomes greater, so that there are more obvious surface effects especially the surface reconstruction and surface relaxation which brings the great effect to the material property. This papers models and analyses the silicon crystal <100> surface reconstruction and relaxation with the molecular dynamics simulation and first principal theory abinitio calculation. During the simulation and calculation, the 2×1Dimer construction is used for the silicon crystal <100>surface reconstruction which is universally applied and testified to be effective, and we also simulate and compare the elastic constants of bulk silicon crystal with the results from literatures. The final simulation results show the elastic constants are very different between silicon film and silicon bulk material, and the thinner the film is, the greater difference between these two kinds of materials.This papers provides some useful theories and simulation ways for the future modeling which combines the classical nonlinear theory, molecular dynamics simulation and abinitio calculation, and also is the basis for the further research on NEMS devices.