Our Present Understanding of the Mechanisms of the transformation of SiO films under treatments in O2 or Ar plasma at room T, is presented. RBS, IR absorption, XPS, RHEED and TEM techniques have been used to investigate the composition, the chemical and structural nature of the films after oxidizing or non oxidizing treatments. In O2 plasma, SiO is converted into Si02 by room T plasma anodization. The initial step of SiO oxidation, which is believed to be the transformation 2SiO→Si+SiO2, was studied in Ar plasma. We show that the as deposited SiO (not a mixture of Si and SiO2) is subject to disproportionate into the later compounds and that the effects of irradiation by low energy electrons at room T (plasma treatment) are similar to those observed for high T treatments (rapid thermal annealing).