金刚石膜厚度尺寸对热残余应力的影响

Effect of Diamond Films Thickness on Thermal Residual Stress

采用有限元方法对钼基体上不同厚度（20～1 000μm）金刚石膜的热残余应力进行了全面的模拟与分析,得出了它们在膜内分布的等值线图,研究了金刚石膜厚度尺寸对整个膜内的最大主拉应力和界面处每个应力分量最大值的影响。结果表明：在整个膜内,最大主拉应力的位置出现在膜的表面、界面或侧面,其值随膜厚度的增加而增大;在界面处,最大轴向应力随膜厚度的增加而增大,而最大径向压应力、最大周向压应力和最大剪应力则随膜厚度的增加而减小,其中最大剪应力减幅较小;膜厚度越大时,以上各量随厚度增（减）的速度越慢。其结论对于在金刚石膜的制备中合理地选择厚度、有效地进行应力控制有一定的参考价值。

Each component of thermal residual stress in diamond films deposited onto Mo substrate was simulated and analyzed comprehensively by using the finite element method,and the different thickness（20～1 000 μm） of the films was used during the simulation.The contour plots of these components distribution were obtained.In addition,the effect of the films thickness on the maximum tensile principal stress in films and on the maximum of every stress component at interface between films and substrate was investigated.The results show that the location of maximum tensile principal stress in the films is at the upward face or side face of the films or the interface,and the magnitude of it increases when the films become thicker.Also,the maximum axial stress at the interface increases when the films become thicker whereas the maximum compressive radial stress,maximum compressive circular stress and maximum shear stress at the interface are in reverse,and the reduction extent of the maximum shear stress is small.The increase or reduction rate of each stress mentioned above is slower when the films thickness becomes larger.These conclusions are useful to choose rationally films thickness and to control effectively the stresses during preparation of diamond films.