| Semiconductor material silicon has played the center role in semiconductor industry since the invention of transistor. It made the advanced electronic industry a firm technology and material base. Although other semiconductor materials have been developed much and have better opto-electronical property than silicon, the silicon material will still be the dominant material in semiconductor industry in next two decades. Thus, the research and development of silicon material will have great influence on the development of economy and society.Silicon is a classic brittle material (i.e., has a low fracture toughness) at room temperature. It is linear elastic until catastrophic fracture, and its fracture is not deterministically predictable. During the fabrication of silicon wafers and devices, if the applied tensile stresses exceed the probabilistic tensile strength of silicon (limiting by the presence of pre-existing flaws), then failure will occur. With the narrowing of the design rules of ULSI devices and the increasing of wafer diameter, maintaining the mechanical strength of silicon wafers becomes one of the most important factors in device fabrication processes. Furthermore, the low density of dislocations typical of the silicon single crystal makes it possible to investigate the mechanism individual dislocations mediate fracture mechanisms. Thus, the investigation of mechanical property of silicon will bring great importance not only to our understanding of the fundamental aspects of the fracture process itself, but also to the application of crystal silicon and development of micro-electronical industiy.However, the research has mainily been focused on the electronical property of silicon material. The other properties related to the application of silicon, especially the effect of the impurities on the mechanical property, are seldom concerned. Thus, we firstly reported the effect of impurities in silicon on the hardness and crack propagating, as well as the fracture characteristics when the initial crack on the orientation of {112} and {112}. It was especially investigated the influence of the nitrogen impurity on the fracture process at room temperature. Meanwhile, the strong pinning effect of nitrogen as well as the heavy doped boron impurity on the dislocations was observed at high temperatures. At last, the stress distribution on whole wafers was analyzed related to the distributaries of oxygen precipitation and dislocations at first time.In this paper, the contact damage and the fracture property of silicon single crystal were investigated at room temperature by indentation and 3-point bending. It was first time to focus on the influence of the intended and unintended impurities to fracture processes and propagation of fracture tips. Also, at high temperatures the behavior of dislocations in silicon single crystal and its interaction with impurities was discussed too. It was found that the contact damage was related to the crystal lattice orientation anisotropy and the dopedimpurities. The damage fractures propagated preferentially on the <110> orientation. Also the doped nitrogen as well as the heavy doped boron atoms increased the hardness. On the contrary, the heavy doped antimony atoms would decrease the hardness. Moreover, the nitrogen atom increased the fracture strength. The nitrogen atom may change the Shockley band of silicon surface and form complexes to influence on the fracture procedure. Thus the dissipation energy during the fracture procedure increased and led to high fracture strength. On the other hand, the nitrogen related complexes and nitrogen atom itself pinned the dislocations efficiently and enhanced the active energy of dislocations at high temperatures. Therefore, the nitrogen doped silicon showed better mechankal property. By using the SDSO laser stress instrument, the stress in wafers was patterned and given an explanation related to the oxygen precipitations and dislocations.In short, the better understanding on the mechanical property of silicon...
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