In a statistical nanoindentation study using a spherical probe, the effect of crystallographic orientation on the phase transformation of silicon (Si) was investigated. The presence and pressure at which events associated with phase transformation occur, for a load range from 20 mN to 200 mN, were analyzed and compared for the orientations Si(001), Si(110)and Si(111). It was found that the plastic deformation combined with the phase transformation during loading was initiated at lower loads (pressures) for Si(110) and Si(111) than for Si(001). Also, the pressure for the phase transformation during unloading was strongly influenced by the crystallographic orientation, with up to 38 % greater values for Si(110) and Si(111) compared to Si(001). Mapping the residual stress field around indentations by confocal Raman spectroscopy revealed significant differences in the stress pattern for the various orientations.
Citation: Journal of Materials Research
Pub Type: Journals
nano-indentation, phase transformation, Si, Raman spectroscopy