In-situ SEM Observation Of A Micro-crack In Single Crystal Silicon And Its Strain Fields

Properties of material is closely related to the micro-structure of the material and thedefects of itself, so that the research of microscopic defects of material is widly attented byresearchers. The micro-crack is a common structure defects in material, and it has a greateffect on the properties of material, the initiation and development of microscopic cracks isalso closed with mechanical properties of material, and can cause the deformation andfailure of material. Therefore, it is very important to study the material micro-crack.Many scholars made a lot of report and research on the stress and strain of material,so as to accelerate the development of strain measurement technique. In recent years,researchers have developed a variety of method what can used for testing and analysisingmaterial deformation fields in microscale combined with the high spatial resolution ofmodern analytical instrument, thereinto, the methods of the peak pairs analysis and thegeometric phase analysis have been used to analysis the high resolution transmissionelectron microscopy images, and could obtain information of the quantitative deformationin nanoscale. But because of it is difficulty of loading in the transmission electronmicroscope, these methods have not yet used for in situ deformation analysis.This article made the silicon pillars array of sub-micron scale on the surface of singlecrystal silicon wafer using the method of combining holographic exposure and plasmaetching technology, and preset a small hole in the center of silicon wafer, then used amethod of in-situ pull stretch of scanning electron microscope, and uniaxial tensile testswere performed on single crystal silicon, and then observed and recorded the process ofinitiation and development of crack under the continuous loads. Respectively, used thePeak Pairs analysis and Geometric Phase analysis to caculate the strain map of micro-crackarea of SEM image of single crystal silicon, and compared the results of the experimentaldata with the linear elastic theory prediction analysis, and can get a conclusion of linearelastic theorety prediction can express micro-crack tip of single crystal silicon in thesub-micro scale, particularly, at far-field region of the micro-crack tip, the experimentalresults and the theoretical predictions are anastomose well.