Gayle Andrew J, Friedman Lawrence H, Beams Ryan, Bush Brian G, Gerbig Yvonne B, Michaels Chris A, Vaudin Mark D, Cook Robert F
Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
J Appl Phys. 2017;122(20). doi: 10.1063/1.5001270.
The strain field surrounding a spherical indentation in silicon is mapped in two dimensions (2-D) using electron backscatter diffraction (EBSD) cross-correlation and confocal Raman spectroscopy techniques. The 200 mN indentation created a diameter residual contact impression in the silicon (001) surface. Maps about area with 128 pixels × 128 pixels were generated in several hours, extending, by comparison, assessment of the accuracy of both techniques to mapping multiaxial strain states in 2-D. EBSD measurements showed a residual strain field dominated by in-surface normal and shear strains, with alternating tensile and compressive lobes extending about three to four indentation diameters from the contact and exhibiting two-fold symmetry. Raman measurements showed a residual Raman shift field, dominated by positive shifts, also extending about three to four indentation diameters from the contact but exhibiting four-fold symmetry. The 2-D EBSD results, in combination with a mechanical-spectroscopic analysis, were used to successfully predict the 2-D Raman shift map in scale, symmetry, and shift magnitude. Both techniques should be useful in enhancing the reliability of microelectromechanical systems (MEMS) through identification of the 2-D strain fields in MEMS devices.
利用电子背散射衍射（EBSD）互相关和共焦拉曼光谱技术在二维（2-D）上绘制了硅中球形压痕周围的应变场。200 mN的压痕在硅（001）表面产生了一个直径为 的残余接触压痕。在几个小时内生成了约128像素×128像素区域的图谱，相比之下，将两种技术的精度评估扩展到二维多轴应变状态的映射。EBSD测量显示残余应变场以表面法向应变和剪切应变为主，拉伸和压缩叶交替出现，从接触点延伸约三到四个压痕直径，并呈现出二重对称性。拉曼测量显示残余拉曼频移场以正向频移为主，同样从接触点延伸约三到四个压痕直径，但呈现出四重对称性。二维EBSD结果与机械光谱分析相结合，成功地在尺度、对称性和频移幅度上预测了二维拉曼频移图谱。这两种技术在通过识别微机电系统（MEMS）器件中的二维应变场来提高微机电系统的可靠性方面都应是有用的。
