In this work, we investigate the extension of the Lawn and Evans indentation fracture model, developed primarily for microscale contact, to nanoscale contacts. Systematic nanoindentation fracture experiments are performed on Si (100) using a sharp diamond cube corner (radius, r = 32 nm) indenter as a function of load, load cycles, contact dimension, and contact separation. Atomic force microscopy is used to image and measure contact deformation and fracture. The experimental results show that the threshold load for fracture was 290 μN, which is lower than previously reported. Adjacent indents separated by less than three times the radius of each indent were observed to interact with each other, such that second indents were consistently deeper than the first at the same loads. There was an increase in crack length for pairs of indents that were separated by equally small distances (<3 indentation radii). These results have clear implications for nanofabrication where stress field interactions impose limits on the closeness (resolution) to which features can be generated and to free abrasive machining where stress field interactions enhance the ability to machine below the threshold load.

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