Generation of vacancies, stimulated by chemical etching of a crystal surface

The formation of non-equilibrium vacancies in crystals which is stimulated by the continuous sampling of the material during the chemical etching of the surface of the sample is considered. A fundamental difference between the mechanism of the chemically stimulated formation of vacancies and the classical Schottky model is pointed out. In the situation being considered, this consists of the fact that the formation of vacancies on the surface of the crystal and their migration into the bulk of the sample are governed by different process parameters: by the rate of etching of the atoms in the normal direction and the temperature of the crystal which can vary over wide limits independently of one another. The requirements regarding the etching conditions are determined (in particular, regarding the microscopic and macroscopic rate and the etching temperature) and also regarding the crystal (defectiveness, point orientations) which are necessary for the realization of the chemically stimulated injection of non-equilibrium vacancies from the surface into the bulk of the sample.