Electron-cyclotron resonance Ar plasma-induced electrical activation of B atoms without substrate heating in B doped Si epitaxial films on Si(100)

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Abstract

Low-energy Ar plasma enhanced decomposition of SiH4 and B2H6 enables B-doped Si epitaxial film formation on Si(100) without substrate heating. For the concentration of B atoms and carriers in the B-doped Si films, depth profiles were investigated. At a fixed partial pressure and microwave power for the deposition, increasing tendency of the concentrations from interface to surface and the lower electrical activation ratio of the B atom for the higher B concentration were clarified. The activation ratio was typically below 1% in the higher B concentration region above 1020 cm−3, while it was as high as above 5% up to 100% in the lower B concentration region below 1019 cm−3. By reducing deposition rate in the fixed Ar plasma condition, the activation ratio in the higher B concentration region was apparently improved. Moreover, effect of post Ar plasma irradiation without substrate heating after about 1.2 nm-thick film deposition was examined for the films with the B concentration of 8 × 1019 cm−3 and initial carrier concentration of 2 × 1019 cm−3. By the post Ar plasma irradiation, 200% enhancement in the activation ratio was successfully observed and the carrier concentration reaches as high as 6 × 1019 cm−3. By increasing the post plasma irradiation time, the activation ratio tended initially to increase and then to degrade. This indicates that Ar plasma irradiation possibly induces incorporation of B atoms at substitutional sites even in nanometer-order deep region beneath surface, while deactivation of the B atoms also proceeds gradually and overtakes the activation finally. These results of plasma-enhanced activation process without substrate heating is expected to be utilized for smart fabrication of semiconductor devices with high carrier concentration and abrupt junction interfaces.

Original languageEnglish
Article number104823
JournalMaterials Science in Semiconductor Processing
Volume107
DOIs
Publication statusPublished - 2020 Mar 1

Keywords

  • Boron
  • Electrical activation
  • Epitaxial growth
  • In-situ doping
  • Plasma chemical vapor deposition
  • Silicon

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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