Figure 2.

Derived relationship between the critical aspect ratio $l/h$ and dimensionless thickness $Eh/G.l$ is the cantilever length, $h$ is the thickness, $E$ is the elastic modulus, and $G$ is the unit area adhesion energy. Three different cantilevers are shown. The critical aspect ratio is the maximum allowable aspect ratio for stable cantilevers to prevent collapse. Here, material properties are set to experimental values reported in the literature^33–35 (i.e., $E=1.6\mathrm{M}\mathrm{P}\mathrm{a}$, $G=4\mathrm{J}/{\mathrm{m}}^2$, and the Poisson’s ratio $v=0.5$).