Controlled carbon doping of GaAs by metalorganic vapor phase epitaxy

Abstract

The controlled incorporation of carbon has been demonstrated for the metalorganic vapor phase epitaxy of GaAs. Carbon levels between 1016 and 1019 cm-3 can be achieved under typical growth conditions by using Ga(CH3)3 and either As(CH 3)3 or mixtures of As(CH3)3 and AsH3. The carbon incorporation into GaAs goes through a minimum with growth temperature at ∼650 °C when using Ga(CH3)3 and As(CH3)3. The controlled addition of AsH3 monotonically decreases the carbon incorporation. The high carbon levels (≳1-2×1019 cm-3), greater than the reported solid solubility, are thermally stable with a low diffusion coefficient. The GaAs:C layers exhibit a low deep level concentration, ∼1013 cm-3, with only a single midgap trap present.