Atomic hydrogen induced defect kinetics in amorphous silicon

TitleAtomic hydrogen induced defect kinetics in amorphous silicon
Publication TypeJournal Article
Year of Publication2017
AuthorsF.JJ Peeters, J. Zheng, I.MP Aarts, A.CR Pipino, W.MM Kessels, M.CM van de Sanden
JournalJournal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films
Date Published09/2017

Near-infrared evanescent-wave cavity ring-down spectroscopy (CRDS) has been applied to study the defect evolution in an amorphous silicon (a-Si:H) thin film subjected to a directed beam of atomic H with a flux of (0.4–2) × 1014 cm−2 s−1. To this end, a 42 ± 2 nm a-Si:H film was grown on the total internal reflection surface of a folded miniature optical resonator by hot-wire chemical vapor deposition. A fully reversible defect creation process is observed, with a nonlinear dependence on H flux, with a time resolution of 33 ms and a relative sensitivity of 10−7. Using polarizing optics, the CRDS signal was split into s- and p-polarized components, which, combined with E-field calculations, provides depth sensitivity. Extensive kinetic modeling of the observed process is used to determine rate constants for the hydrogen–material interactions and defect formation in a-Si:H, as well as revealing a high diffusion coefficient for atomic H on the order of 10−11 cm2 s−1. A novel reaction pathway is proposed, whereby H inserted into weak Si–Si bonds recombines with mobile H, resulting in a limited penetration depth for atomic H from the gas-phase on the order of 10–15 nm.





Alternate TitleJ. Vac. Sci. Technol. A

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