Observation of interstitial carbon in heavily carbon-doped GaAs

Nuclear reaction analysis, utilizing the 12C(d, p)13C reaction, in conjunction with Rutherford backscattering spectrometry in the channeling geometry were used to determine the lattice locations of carbon in heavily carbon-doped GaAs samples with carbon concentrations greater than 5×1019 cm−3. The data unambiguously show that at least 25% of the carbon atoms occupied interstitial sites within the channels of the GaAs crystal. The existence of interstitial carbon is important for practical applications since the atomic diffusivity of interstitial carbon may be different from that observed in GaAs when carbon is only incorporated substitutionally.