The Study Of Resonance Characteristics Of Silicon Nanowires Based On Molecular Dynamics Simulation

Due to the rapid development of semiconductor technology, process line narrows from level micron to nanometer level gradually, and it makes NEMS get an even broader application.But NEMS is also faced with the problems of the research methods, manufacturing technology, laboratory equipment, etc. With the scale of the material reaching nanometer level, size effect, surface effect and quantum effect on the properties of materials will be more obvious, the influence of these even becomes the bottleneck of development of nanometer materials. Accurately describing the physical properties of nanomaterials has become the key factor to designing, manufacturing, optimization of nano device.Silicon nanowires is a typical representative of one-dimensional silicon nanomaterials,it also shows many physical properties such as field emission, thermal conductivity and visible luminescence which are different from silicon materials, in addition to the special properties of the semiconductor.It has great potential application value in nanoscale electronic devices, optoelectronic devices and new energy. Therefore silicon nanowires may be the core unit in the construction of mechanical and electrical system in future. In recent years the manufacturing processes of silicon nanowires has a great development, people can manufacture silicon nanowires in different sections and directions, and we have explored some properties by means of experiment. But some physical characteristics is unable to be explained on the basis of existing theory, one of them is the resonant frequency of silicon nanowires. In recent years, due to the wide application on the components such as resonators and oscillators of silicon nanowires, the research on the resonance frequency of has become a hot spot. With the reduce of size, the frequency of silicon nanowires keeps on getting bigger from several megabytes to hundreds of megabytes, finally to GHz.people haven’t seen any patterns evolve about the frequency of silicon nanowires yet.In this paper, we study the resonant characteristics based on the molecular dynamics by using material studio software. we study the resonance frequency of silicon nanowires in the direction of< 111>,< 110>, < 112>.we consider the effect of crystal orientation, size (length, width, thickness) and surface structure(cross section shape, surface reconstruction) on its resonant frequency respectively.Results show that the frequency of silicon nanowires is not fully complied with Euler Bernoulli beam theory because of the different environment of surface atoms and the atoms in the body. The resonance frequency of silicon nanowires in direction< 111>,< 110>and< 112> falls off as the square of length approximately but has no relation with the width of cross section. However, the increase of width will leads to the increase of thickness inevitably, so the resonant frequency of silicon nanowires will produce a slight drift. In< 111> direction, because of the different influence of surface, the resonant frequency of silicon nanowires with different sections is also different. It can be found that found that surface reconstruction has a significant influence on the resonant frequency of silicon nanowires through simulation.In this paper, we presents the AFM probe model, it makes the silicon nano beam vibrate by using the van der Waals forces between the molecules. These models provide a new idea for studying and designing NEMS devices in the future. And they are also a reference for the theoretical research of silicon nanowires.