Face Turning of Single Crystal (111)Ge: Cutting Mechanics and Surface/Subsurface Characteristics
Face Turning of Single Crystal (111)Ge: Cutting Mechanics and Surface/Subsurface Characteristics
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单晶 (111)Ge 的端面车削：切削力学和表面/次表面特性
DOI：
10.1115/1.4057054
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Lucca, D. A.
中科院分区：
文献类型：
--
作者：
Zare, A.;Tunesi, M.;Harriman, T. A.;Troutman, J. R.;Davies, M. A.;Lucca, D. A.
单晶锗是一种具有广泛应用的半导体，特别是在红外光的操纵方面。金刚石加工能够有效地生产光学工业要求的公差表面。在各向异性单晶加工过程中，相对于面内晶格取向的切削方向对表面和次表面的最终质量起着至关重要的作用。在本研究中，在未掺杂的（111）Ge晶圆上进行了轴向面车削实验，以研究晶体各向异性和进给速度对表面和表面下条件的影响。原子力显微镜和扫描白光干涉测量法用于表征加工表面脆性断裂的存在，并评估由此产生的表面粗糙度。利用拉曼光谱分析了刀具在加工过程中引起的残余应力和晶格紊乱。采用Berkovich和立方体角压头进行纳米压痕，以评估加工表面的弹性模量、硬度和断裂韧性，并研究它们随进给速度和切削方向的变化。对选定的压痕进行压痕后研究，以表征相应的准塑性机制。研究发现，进给量的增加会产生刀具传递的合力的旋转，表明从压痕主导转向切削主导。断口随进给速度的增加而增加，当切削方向属于该类时，断口倾向更高。
Single crystal Ge is a semiconductor that has broad applications, especially in manipulation of infrared light. Diamond machining enables the efficient production of surfaces with tolerances required by the optical industry. During machining of anisotropic single crystals, the cutting direction with respect to the in-plane lattice orientation plays a fundamental role in the final quality of the surface and subsurface. In this study, on-axis face turning experiments were performed on an undoped (111)Ge wafer to investigate the effects of crystal anisotropy and feedrate on the surface and subsurface conditions. Atomic force microscopy and scanning white light interferometry were used to characterize the presence of brittle fracture on the machined surfaces and to evaluate the resultant surface roughness. Raman spectroscopy was performed to evaluate the residual stresses and lattice disorder induced by the tool during machining. Nanoindentation with Berkovich and cube corner indenter tips was performed to evaluate elastic modulus, hardness, and fracture toughness of the machined surfaces and to study their variations with feedrate and cutting direction. Post-indentation studies of selected indentations were also performed to characterize the corresponding quasi-plasticity mechanisms. It was found that an increase of feedrate produced a rotation of the resultant force imparted by the tool indicating a shift from indentation-dominant to cutting-dominant behavior. Fracture increased with the feedrate and showed a higher propensity when the cutting direction belonged to thefamily.