单晶锗纳米切削特性广义质点动力学方法与实验研究

Generalized Particle Dynamics Method and Experimental Study of Crystalline Germanium Nano-Cutting Characteristics

为提高纳米级锗器件的制造精度,提出一种广义质点动力学(GP)分析方法,该方法是一种多尺度分析方法,能够在保证材料晶体结构不变的前提下,大量节省计算时间,扩大模拟规模,使可模拟的材料区域增加几个量级。建立了单晶锗广义质点动力学纳米切削模型,修正了单晶锗相互作用势能函数,绘制了在不同载荷下的切削力-刻划距离曲线图,分析了在切削过程中切削力及切屑堆积状态的变化情况。使用纳米划痕仪对单晶锗进行了纳米刻划实验,得到当载荷在10~30 mN变化时,沟槽的深度变化范围为1.12~1.88 nm,宽度变化范围为4.6~8.6μm,实验结果与广义质点动力学得到的结果趋势相一致,证明了该方法的有效性。与分子动力学方法相比,在对体系较大的模型应用这种方法能够在保证计算精度的前提下节省大量计算时间。

In order to improve the manufacturing precision of nanoscale germanium devices, a generalized particle dynamics(GP) analysis method was proposed, which was a multi-scale analysis method. Under the condition that the crystal structure of the material was constant, the calculation time was saved a lot, and the scale of simulation could be expanded, and the simulated area of the material could be increased by several orders of magnitude. In this paper, a generalized particle dynamic nano-cutting model of single crystal germanium was established, and the interaction potential energy function of the single crystal germanium was corrected. Also, the cutting force-scratch distance curves under different loads were plotted, and the changes of cutting force and chip accumulation state during the cutting process were analyzed. Furthermore, nano-scratch experiment on single crystal germanium was conducted by using the nano scratch tester. The results showed that: when the load was 10~30 mN, the depth of the groove varied from 1.12~1.88 nm and the range of width was 4.6~8.6 μm. The experimental results were consistent with that obtained by the generalized particle dynamics, which proved the effectiveness of the method. Compared with the molecular dynamics method, this method can save a lot of calculation time in the large system model on the premise of guaranteeing the accuracy of calculation.