This thesis investigates a surface nanohole toughening method which relieves stress concentration around the V-shaped notch. Using electroless metal deposition, this work fabricates the above mentioned structure, and matains the single crystal silicon properties.
The anisotropic etchant TMAH etches along the specific crystal direction and forms a V-shaped notch with a groove degree of 70.53°. This notch dominates the whole fracture behavior; only the crack propagates along this notch. The rupture load of bare Si is about 30.9 N. Depth of the V-shaped notch after forming is 2 μm, and the rupture load is 18.1 N; when depth reaches 14 μm, the rupture load decreases to 6.3 N.
Nanoholes form on the pre-notch plate, designing three different depth nanoholes : half of notch depth; equal to notch depth; one half of notch depth. According to a three point bending test, when nanohole depth is half of notch, it recovers and toughens the plate. The strength of 2 μm and 14 μm plate both enhance by nanoholes to 2.62 times and 5.57 times individually.

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