The effects of background doping, surface encapsulation, and As4 overpressure on carbon diffusion have been studied by annealing samples with 1000 Å p-type carbon doping spikes grown within 1 μm layers of undoped (n-), Se-doped (n+), and Mg-doped (p+) GaAs. The layers were grown by low-pressure metalorganic chemical vapor deposition using CCl4 as the carbon doping source. Two different As4 overpressure conditions were investigated: (1) the equilibrium pAs4 over GaAs (no excess As), and (2) pAs4 ∼2.5 atm. For each As 4 overpressure condition, both capless and Si3N 4-capped samples of the n--, n+-, and p +-GaAs crystals were annealed simultaneously (825°C, 24 h). Secondary-ion mass spectroscopy was used to measure the atomic carbon depth profiles. The carbon diffusion coefficient is always low, but depends on the background doping, being highest in Mg-doped (p+) GaAs and lowest in Se-doped (n+) GaAs. The influence of surface encapsulation (Si 3N4) and pAs4 on carbon diffusion is minimal.

Original languageEnglish (US)
Pages (from-to)687-689
Number of pages3
JournalApplied Physics Letters
Issue number7
StatePublished - Dec 1 1989

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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    Cunningham, B. T., Guido, L. J., Baker, J. E., Major, J. S., Holonyak, N., & Stillman, G. E. (1989). Carbon diffusion in undoped, n-type, and p-type GaAs. Applied Physics Letters, 55(7), 687-689. https://doi.org/10.1063/1.101822