Anisotropic etching of silicon crystals in KOH solution

The anisotropic etching behaviour of various crystalline silicon plates in an aqueous KOH solution was studied. Variations of the etch rate with the angle of cut related to singly-rotated plates have been determined and orientation effects in the out-of-roundness profiles related to various {h k 0} sections have been analysed in terms of crystal symmetry. In addition, changes in the surface texture with crystal orientation were systematically investigated. All the experimental results furnished evidence for a dissolution process governed by the crystal orientation. A procedure has been proposed to derive the dissolution slowness surface from experiments starting from a tensorial representation of the anisotropic etching.