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Title: Etching of a-Si:H thin films by hydrogen plasma: A view from in situ spectroscopic ellipsometry

When atomic hydrogen interacts with hydrogenated amorphous silicon (a-Si:H), the induced modifications are of crucial importance during a-Si:H based devices manufacturing or processing. In the case of hydrogen plasma, the depth of the modified zone depends not only on the plasma processing parameters but also on the material. In this work, we exposed a-Si:H thin films to H{sub 2} plasma just after their deposition. In situ UV-visible spectroscopic ellipsometry measurements were performed to track the H-induced changes in the material. The competition between hydrogen insertion and silicon etching leads to first order kinetics in the time-evolution of the thickness of the H-modified zone. We analyzed the correlation between the steady state structural parameters of the H-modified layer and the main levers that control the plasma-surface interaction. In comparison with a simple doped layer, exposure of a-Si:H based junctions to the same plasma treatment leads to a thinner H-rich subsurface layer, suggesting a possible charged state of hydrogen diffusing.
Authors:
; ;  [1] ;  [2]
  1. Laboratoire d’Ingénierie et Sciences des Matériaux (LISM, EA 4695), Université de Reims Champagne-Ardenne (France)
  2. Laboratoire de Physique des Interfaces et Couches Minces (LPICM, CNRS UMR 7647), Ecole Polytechnique (France)
Publication Date:
OSTI Identifier:
22419839
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CONTROL; DEPOSITION; DOPED MATERIALS; ELECTRIC CONTACTS; ELLIPSOMETRY; ETCHING; HYDROGEN; INTERACTIONS; KINETICS; PLASMA; SILICON; SURFACES; THIN FILMS