Even for samples exhibiting excellent electronic properties in terms of carrier mobility, sample‐to‐sample variability remains considerable and dislocation density is still very high, the latter characteristic being often related to damages induced either by the substrate polishing step or by substrate bulk dislocations. In order to limit the polishing effect, a pre‐treatment based on H₂/O₂ plasma etching under relatively high pressure (a few 100 mbar) has been routinely used for several years. Nevertheless, those bulk dislocations present in the substrate that reach its surface lead to square etch‐pit formation which depth can grow to several 100 nm, preventing the growth of smooth and flat thin films (2/O₂ plasma pre‐treatment advantages, even for thin film deposition with smooth surface.