Growth and characterization of carbon-doped low-temperature GaAs

Abstract

We present the results of double crystal X-ray diffraction and infrared absorption measurements on C-doped low-temperature GaAs (LT-GaAs:C) layers grown by solid source molecular beam epitaxy at different growth temperatures T G and C concentrations. Strain compensation is achieved at T G=220°C with a C concentration of 2.5×10 19 cm −3. The density of As Ga antisite point defects and the incorporation of C is studied by IRA. At T G=250°C and high C concentrations, we observe a drastic decrease in the intensity of the local vibrational mode of substitutionally incorporated C As. Simultaneously, new local vibrational modes appear whose intensity increases by a further lowering of T G. This result, which is neither observed at low C concentrations nor in the heavily doped GaAs:C grown at conventional T G, is ascribed to the formation of CC complexes in heavily doped LT-GaAs:C.