Influence of initial surface damage on the final texture of chemically etched quartz plates

Various AT-cut quartz plates, mechanically lapped or polished prior to etching are etched at a constant temperature. The variations in the dissolution rate with the time of etching are found to depend on the surface damage in the initial stages of the chemical attack, but with prolonged etching all the dissolution rates tend to a common limiting value. Lapped and polished quartz plates exhibit opposite changes in roughness parameters with the depth of etch for short etching times. Subsequent dissolution leads, whatever the original surface preparation of the quartz plate, to equilibrium values of the roughness parameters characterized by the direction of the profilometry traces. Scanning electron micrographs are in agreement with these observations and reveal that pits of the same shape develop on polished and lapped quartz plates. Thus the initial surface damage has no influence on the final surface texture of deeply etched quartz plates which is determined primarily by the crystal orientation.