Intrinsic strength of silicon crystals in pure- and combined-mode fracture without precrack.
Measurement of the critical fracture strength of single-crystal silicon was carried out by contact-free laser-based excitation and detection of nonlinear surface acoustic wave (SAW) pulses. The three crystallographic geometries Si(112)111[over ], Si(112)1[over ]1[over ]1, and Si(110)11[over ]1 were examined. A comparison of the optically detected SAW transients and numerically calculated stress-strain fields allowed an estimate of the intrinsic mechanical strength without using an artificial precrack. Depending on the geometry, the critical strength varied between 5 and 7 GPa.
Institute of Physical Chemistry, University of Heidelberg, Im Neuenheimer Feld 253, D-69120 Heidelberg, Germany.
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Kozhushko
A M
AM
Lomonosov
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P
Hess