Mechanism for convex corner undercutting of (110) silicon in KOH

Abstract The cantilever is fabricated on (110) silicon wafer by anisotropic wet etching method in KOH; the sidewall of cantilever is {111} plane, and it is vertical to the substrate. The convex corner is undercut, and the concave corner structure corresponds with the design. The mechanism of the convex corner undercutting is explained by the theory of covalent bond density.