Capabilities and Limitations of RBS to Characterize Hyper-Thin Silicon Compound Layers on Various Polymeric Substrates

Abstract

Rutherford backscattering spectroscopy (RBS) expts. were performed using 1 and 1.5 MeV He2+ ions to study SiO2 and SiN gas barrier layers deposited by plasma-enhanced CVD on org. polymeric substrates. Three different polymeric substrates were used, i.e., Kapton polyimide (PI), Mylar polyethyleneterephthalate (PET), and Lexan polycarbonate (PC). In the case of Kapton PI, no artifacts were obsd. despite chem. modifications of the polymer. The surface concn. of silicon is proportional to the time of deposition. For Lexan PC and Mylar PET, both known to be more fragile than Kapton PI, major artifacts appeared during RBS measurements. The high concns. of volatile mol. fragments liberated by chain scission and crosslinking reactions during irradn. by energetic ions, even under very mild beam conditions, appeared to be the cause of these artifacts. [on SciFinder (R)]