Characterization of in-depth cavity distribution after thermal annealing of helium-implanted silicon and gallium nitride

B. Fodor, F. Cayrel, E. Agocs, D. Alquier, M. Fried, P. Petrik

Research output: Article

2 Citations (Scopus)

Abstract

Single-crystalline silicon wafers covered with sacrificial oxide layer and epitaxially grown gallium nitride layers were implanted with high-fluence helium ions (2-6 × 1016 cm- 2) at energies of 20-30 keV. Thermal annealings at 650-1000 °C, 1 h were performed on the Si samples and rapid thermal annealings at 600-1000 °C, 120 s under N2 were performed on the GaN samples. The as-implanted samples and the near-surface cavity distributions of the annealed samples were investigated with variable angle spectroscopic ellipsometry. In-depth defect profiles and cavity profiles can be best described with multiple independent effective medium sublayers of varying ratio of single-crystal/void. The number of sublayers was chosen to maximize the fit quality without a high parameter cross-correlation. The dependence of the implantation fluence, oxide layer thickness and annealing temperature on the cavity distribution was separately investigated. The ellipsometric fitted distributions were compared and cross-checked with analyses of transmission electron micrographs where the average surface cavity was determined sublayer by sublayer. The in-depth profiles were also compared with simulations of He and vacancy distributions.

Original languageEnglish
Pages (from-to)567-572
Number of pages6
JournalThin Solid Films
Volume571
Issue numberP3
DOIs
Publication statusPublished - nov. 28 2014

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

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