Mechanical Strengthening Property of SiC Material Covered with Multilayer Graphene From Molecular Dynamic Simulation

A large number of practices have shown that under the coupling influence of complex working conditions and frequent reciprocating contact, the surface of semiconductor devices in micro/nano electromechanical systems often produces adhesive wear, which is the essential reason result in short durability service life and decline in contact mechanical properties for microelectronics semiconductor devices. However, graphene can significantly improve the interface properties of mechanical and electronic components due to its excellent mechanical properties, such as high carrier concentration, good thermal conductivity, and low shear. Thus, this study of mechanical strengthening properties and plastic deformation of SiC material with covered multi-layer graphene in MEMS devices will play a significant role in improving the durability service life of MEMS devices, and understanding its strengthening and toughening mechanism. Therefore, this paper studies and discusses the effects of stacking type and extreme service temperature with low and high levels on the contact mechanical properties (maximum load, hardness, Young modulus, contact stiffness), micro-structure evolution, contact mass, fold morphology, and total length of dislocation. The atomic-scale mechanism of enhanced mechanical properties of SiC material with multi-layer graphene is explained. The research shows that the damage of carbon-carbon bond during the maximum indentation depth will lead to the loss of the excellent in-plane elastic deformation ability of graphene when the graphene stacking type is AB stacking, so that the maximum load-bearing capacity of the substrate covered by three layers of graphene will drop linearly. In addition, the mechanical properties of SiC material coated with three graphene layers are twice than that pure SiC substrate, and the strengthening mechanism is mainly due to the increase of folds caused by the increase of multilayer graphene loading, which causes the contact quality between the SiC substrate and the virtual indenter to decrease, thus increasing the interface contact stiffness. The increase of the active temperature will stimulate the increase of the atomic vibration frequency, which will cause the number of interface contact atoms to increase greatly, and the interface contact stiffness will weaken, and finally lead to the increase of interface contact quality. This reason is that the mechanical properties of SiC substrate coated with multilayer graphene will decrease approximately linearly with the extreme services low temperature to high temperature. In addition, the stress concentration in the subsurface layer of SiC substrate can induce the evolution of its micro-structure, and the increase of the number of graphene layers on the substrate can effectively reduce the stress concentration distribution in the subsurface layer of the substrate.