Abstract
The effect of the concentration of (NH4)2S2O8 and NH4OH on dissolution of the copper (111) surface in Young’s etchant ((NH4)2S2O8-NH4OH-NH4Br) was studied by utilizing the etch-pits of edge dislocations. The dissolved thickness S of the matrix surface was first measured by two-beam interferometry. The two quantities H and D correlating with the dissolution of the copper (111) surface in lateral and normal directions at the dislocation sites were determined from S and the width h and depth d of the edge dislocation etch pit which were measured by replica electron microscopy.
As the concentration of (NH4)2S2O8 and NH4OH in the etchants was increased, the following features were confirmed: (a) the lateral dissolution at the edge dislocation sites, H, increased gradually, (b) the normal dissolution at the edge dislocation site, D, showed a maximum at a certain concentration and (c) the matrix dissolution, S, increased slightly.
These results were discussed on the basis of the two-dimensional nucleation theory of crystal dissolution.
