SiCN/Si在纳米压痕过程中的塑性性能

Plastic Properties of SiCN/Si during Nanoindentation

通过建立的SiCN/Si薄膜/基体系统,提出了一种分析纳米压痕过程中材料塑性性能的方法。用有限元方法模拟了纳米压痕过程,通过比对模拟和实验所得的载荷—压深曲线,反复修正,得到了SiCN薄膜的应力—应变曲线。同时模拟了不同最大压深下薄膜内应力的分布规律,以及残余深度与最大压深的关系。计算得到SiCN薄膜的塑性性能为:屈服强度9.2 GPa、应变硬化指数0.3和强化系数23.45 GPa。当压痕深度较大时,薄膜将受到基体的影响,综合考虑最大压痕深度不得超过薄膜厚度的10%。克服了原有纳米压痕方法无法获得塑性性能的局限性,为薄膜力学稳定性分析奠定了基础。

An innovative method for analyzing the plastic properties of materials during nanoindentationis established from the film/substrate system of SiCN/Si.The nanoindentation process is simulated by the finite element method.The stress-strain curves of SiCN film is obtained by repeatedly calibrating the loaddepth curves obtained by simulation and experiment.Meanwhile,the distribution of the internal stress of the film under different maximum pressure depths,as well as the relationship between the residual depth and the maximum pressure depth,are simulated.The plastic properties of SiCN films is calculated,namely,the yield strength is9.2GPa,the strain hardening exponent is0.3,and the strengthening coefficient is23.45GPa.When the indentation depth is large,the film will be affected by the substrate,so the maximum indentation depth should not exceed10%of the film thickness under comprehensive consideration.This overcomes the limitations of the original nanoindentation method which cannot obtain the plastic property,and lays out the foundation for stability analysis of film mechanics.