Morphology and semiconducting properties of homoepitaxially grown phosphorus-doped (1 0 0) and (1 1 1) diamond films by microwave plasma-assisted chemical vapor deposition using triethylphosphine as a dopant source

Takeyasu Saito, Masanori Kameta, Katsuki Kusakabe, Shigeharu Morooka, Hideaki Maeda, Yasunori Hayashi, Tanemasa Asano, Akihiko Kawahara

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7 Citations (Scopus)

Abstract

Phosphorus-doped (1 0 0) and (1 1 1) diamond films were homoepitaxially formed on nondoped diamond films, which had been also formed homoepitaxially on type-Ib (1 0 0) and (1 1 1) diamond substrates, respectively, by microwave plasma-assisted chemical vapor deposition. Methane and triethylphosphine (TEP, P(C2H5)3) were used as the carbon and dopant sources, respectively. When the P/C ratio in the gas phase was in the range of 10-2-10-1 and the methane concentration was 0.5%, smooth homoepitaxial (1 0 0) diamond films with a thickness of approximately 800 nm were obtained at 1123 K. Raman spectroscopy showed that the P-doped (1 0 0) diamond films formed with gas phase P/C ratios higher than 4 × 10-2 contained sp2 carbon. Phosphorus was found to be uniformly incorporated in the films, as evidenced by secondary ion mass spectroscopy, and the phosphorus concentration in the doped (1 0 0) diamond films was estimated to be (2-8) × 1018 cm-3. All P-doped (1 0 0) diamond films showed insufficient ohmic contacts for a Hall-effect determination, and no n-type conduction was confirmed. However, a homoepitaxial (1 1 1) diamond film, which was formed at 1173 K using a gas-phase P/C ratio of 5 × 10-3 and a methane concentration of 0.1% on a nondoped homoepitaxial (1 1 1) diamond layer at 1123 K exhibited n-type conduction at temperatures higher than 485 K. The carrier concentration and Hall mobility at 500 K were 3.8 × 1016 cm-3 and 38 cm2/V s, respectively. Phosphorus was uniformly incorporated in the film at a concentration of 1 × 1020 cm-3.

Original languageEnglish
Pages (from-to)723-733
Number of pages11
JournalJournal of Crystal Growth
Volume191
Issue number4
DOIs
Publication statusPublished - Aug 1 1998
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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