Thickness-Dependent Defect Structure of Epitaxial Silicon Thin Films Deposited by Hot-Wire Chemical Vapor Deposition

H. R. Moutinho, D. L. Young, K. Alberi, C. S. Jiang, K. M. Jones, M. M. Al-Jassim

Research output: Contribution to conferencePaperpeer-review


In this work, we study the defect structure of epitaxial film silicon grown by hot-wire chemical vapor deposition (HWCVD) on Si wafers, as a function of film thickness. We used scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to investigate the distribution, type, and composition of the defects. To investigate the crystallographic structure, we used electron backscattering diffraction (EBSD) on the surface and cross sections of the samples. We observed that, as desired, the films grew epitaxially, and that there was an increase in the density of defects as the film thickness increased. One of the most dominant types of defects grows as long columns, reaching many micrometers in diameter at the surface. EBSD showed that these defects were composed of randomly oriented polycrystalline-silicon grains. To study the electrical nature of the film and defects, we used conductive atomic force microscopy (C-AFM), which provides information on film conductivity with high-spatial resolution. C-AFM showed that the columnar defects have much lower conductivity than the surrounding Si thin film. In this work, we show how the concentration and distribution of the defects change as the film thickness increases, and investigate their electrical properties. Finally, we discuss how the defect structure might impact solar cells made with this material.

Original languageAmerican English
Number of pages5
StatePublished - 2011
Event37th IEEE Photovoltaic Specialists Conference, PVSC 2011 - Seattle, WA, United States
Duration: 19 Jun 201124 Jun 2011


Conference37th IEEE Photovoltaic Specialists Conference, PVSC 2011
Country/TerritoryUnited States
CitySeattle, WA

NREL Publication Number

  • NREL/CP-5200-50834


  • chemical vapor deposition
  • epitaxial film silicon
  • photovoltaics
  • solar cells


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