COMPUTATION Mechanical properties and deformation behaviors of surface-modified silicon: a molecular dynamics study Juan Chen 1 , Junqin Shi 1 , Zhi Chen 1 , Meng Zhang 1 , Weixiang Peng 1 , Liang Fang 1,2, *, Kun Sun 1, *, and Jing Han 3 1 State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China 2 School of Mechanical and Electrical Engineering, Xiamen University Tan Kah Kee College, Zhangzhou 363105, China 3 School of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China Received: 1 June 2018 Accepted: 19 October 2018 Ó Springer Science+Business Media, LLC, part of Springer Nature 2018 ABSTRACT The mechanical properties and deformation behaviors of monocrystalline sili- con coated by an amorphous SiO 2 film with different thicknesses are explored by nanoindentation process with molecular dynamics (MD) simulation. The results indicate that the calculated indentation modulus increases with the growing indentation depth for monocrystalline silicon with and without amorphous SiO 2 film, while the modulus decreases with increasing film thick- ness at the same indentation depth. The derived hardness during indentation process, which is more sensitive to amorphous SiO 2 film thickness, is complex due to the plastic deformation of SiO 2 film, illustrating a deformation-induced softening behavior. The plastic deformation of amorphous SiO 2 film exhibits four periods during whole indentation process, namely densification, densifi- cation–rupture transition, rupture during loading and elastic recovery during unloading, which are reasonably verified by CN number of silicon atoms and Si–O bond number within SiO 2 film as a function of indentation depth. It is concluded that the SiO 2 film acts as a medium to dissipate the energy and to transmit the stress from indenter to underlying silicon substrate. The MD results show that the differences of phase distribution between silicon with and without SiO 2 film at the same penetration depth are driven by the stress. Introduction Silicon wafers have been widely used as a construc- tion and function material in the micro-electron mechanical (MEMS) systems [1], solar panel and ultra-large-scale integrated circuit (ULSI) [2]. Espe- cially in ULSI, the shrinking chip element sizes and increasing wafer diameter require simultaneously global and local high-precision planarization of sur- face [3]. Chemical mechanical polishing (CMP) is Address correspondence to E-mail: fangl@xjtu.edu.cn; sunkun@xjtu.edu.cn https://doi.org/10.1007/s10853-018-3046-1 J Mater Sci Computation