“…27 Van Hest et al 20 and Rich et al 25 reported that atomic oxygen reacts easily with Si-CH 3 , Si-H, Si, and CH 3 groups of the pp-HMDSO film. SF 6 plasma, providing the reactive etchant fluorine atoms, 28 was previously and successfully used for the enhancement of polymers hydrophobicity, [29][30][31] while for pp-HMDSO thin film surface modification, an elevated etching rate (≈90 nm/min) of this material in SF 6 plasma was reported, making it a potential candidate in the area of designing high-aspect ratio microelectromechanical systems. 32 The technological motivation behind our present work, which deals with the surface modification of pp-HMDSO thin films by two reactive plasmas (SF 6 and O 2 plasmas), is to investigate, besides the already reported properties mentioned above, particularly in O 2 plasma, other films properties, such as film density and thickness, optical band gap, and electrical resistivity.…”