Fracture strength analysis of single-crystalline silicon cantilevers processed by focused ion beam

• Quantitative fracture strength of Si micro-components (cantilevers) fully processed via FIB is shown.
• Possibility of substituting mask-etch-processed test elements by FIBed prototypes is discussed on the basis of the above results.
• Fracture criterion for Si micro-components is confirmed via our original methodology of using different types of cantilevers.
• Special methodology of fabricating FIB specimens is documented in detail.

The fracture strength properties of single-crystalline Si micro-components fully processed via focused ion beam were successfully evaluated by an in situ nano-mechanical testing system. Fracture initiation of all tested specimen was completely brittle within the detection limit of the testing system. By using different types of cantilever specimens (smooth/notched), it was suggested that the fracture initiation along the {1 1 1} plane was controlled primarily by the critical normal stress component regardless of the magnitude of shear stress component. The average strength value for FIB-processed specimens (σc = 8.1 GPa) was found to be approximately the same as that of wet-etch-processed specimens while larger than that of dry-etch-processed specimens.