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Title: High-temperature degradation in plasma-enhanced chemical vapor deposition Al{sub 2}O{sub 3} surface passivation layers on crystalline silicon

In this publication, the activation and degradation of the passivation quality of plasma-enhanced chemical vapor deposited aluminum oxide (Al{sub 2}O{sub 3}) layers with different thicknesses (10 nm, 20 nm, and 110 nm) on crystalline silicon (c-Si) during long and high temperature treatments are investigated. As indicated by Fourier Transform Infrared Spectroscopy, the concentration of tetrahedral and octahedral sites within the Al{sub 2}O{sub 3} layer changes during temperature treatments and correlates with the amount of negative fixed charges at the Si/Al{sub 2}O{sub 3} interface, which was detected by Corona Oxide Characterization of Semiconductors. Furthermore, during a temperature treatment at 820 °C for 30 min, the initial amorphous Al{sub 2}O{sub 3} layer crystallize into the γ-Al{sub 2}O{sub 3} structure and was enhanced by additional oxygen as was proven by x-ray diffraction measurements and underlined by Density Functional Theory simulations. The crystallization correlates with the increase of the optical density up to 20% while the final Al{sub 2}O{sub 3} layer thickness decreases at the same time up to 26%. All observations described above were detected to be Al{sub 2}O{sub 3} layer thickness dependent. These observations reveal novel aspects to explain the temperature induced passivation and degradation mechanisms of Al{sub 2}O{sub 3} layers at a molecular level like themore » origin of the negative fixe charges at the Si/SiO{sub x}/Al{sub 2}O{sub 3} interface or the phenomena of blistering. Moreover, the crystal phase of Al{sub 2}O{sub 3} does not deliver good surface passivation due to a high concentration of octahedral sites leading to a lower concentration of negative fixed charges at the interface.« less
Authors:
 [1] ;  [2] ; ; ;  [1] ;  [3] ;  [2] ;  [4]
  1. Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstraße 2, D-79110 Freiburg (Germany)
  2. (Germany)
  3. Freiburg Materials Research Center FMF, Albert-Ludwigs-Universität Freiburg, Stefan-Meier-Straße 21 (Germany)
  4. Department of Microsystems Engineering IMTEK, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg (Germany)
Publication Date:
OSTI Identifier:
22314568
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALUMINIUM OXIDES; BLISTERS; CHEMICAL VAPOR DEPOSITION; CRYSTALLIZATION; CRYSTALS; DENSITY FUNCTIONAL METHOD; FOURIER TRANSFORM SPECTROMETERS; INTERFACES; LAYERS; ORIGIN; PASSIVATION; PLASMA; SEMICONDUCTOR MATERIALS; SILICON; SILICON OXIDES; SIMULATION; SURFACES; THICKNESS; X-RAY DIFFRACTION