Effect of prolonged holding under contact loading on the peculiarities of phase changes in silicon

Abstract

It was shown that prolonged holding under the peak load during indentation of Si (100) led to the creep of material even at room temperature that became possible due to the phase transition into more plastic metallic b-Sn phase. The end structural phases in the indentation zone, studied by micro-Raman spectroscopy were found to be affected by the longer holding under the load and demonstrated more intensive peaks for amorphous phase (a-Si) in the depth of the indentation comparatively with those for short holding indentations. It was suggested that this effect was caused by the activation of the dislocation mechanism of a-Si formation, as a result of longer shear stresses action under prolonged holding. This fact induced some changes in the kinetics of the unloading events, which demonstrated the tendency to the “kink pop-out” formation instead of typical “pop-out” and “elbow”.