Ordered shapes of the CVD SiO2 evinced by wet etching

As we know, both grown and deposited SiO₂ is considered an amorphous material. A lot of experiments based on the silicon dioxide etching showed a series of micro and nano-formations which lead to a polycrystalline structure assumption. This paper is focused on the “crystalline” form of the SiO₂ after a wet etching in NH₄F:CH₃COOH solution. In order to modify the selectivity of the mixture, we have tested 3 different concentrations. There were performed a lot of investigations using SEM, AFM and Optical microscopy.