Radiation enhanced transport of hydrogen in SiO2

Abstract 2.2 MeV 4 He + and 7 MeV 15 N 2+ ion beams have been used to investigate, by in situ measurements, the hydrogen desorption processes in SiO 2 thin films deposited by plasma enhanced chemical vapor deposition (PECVD). An effective cross-section of 3 × 10 −16 cm 2 for He and 17 × 10 −16 cm 2 for N has been measured for the ion-thin-film interaction phenomena. The structure crystalline silicon/thermally grown SiO 2 /PECVD film has also been investigated for the hydrogen radiation-enhanced diffusion in thermally grown SiO 2 . The data are consistent with a diffusion process with a diffusion coefficient of (5.0 ± 0.5) × 10 −26 cm 2 /ion from a constant source at a concentration C 0 = (2.5 ± 0.2) × 10 21 at/cm 3 .