ABSTRACT
Heavily carbon doped GaAs-layers with hole concentrations up to 1.6*1020 cm-3 were grown by low-pressure MOVPE using carbon tetrabromide as doping source. Specular layer morphologies and hole mobilities comparable with literature data were obtained in the temperature region 550°C - 670°C. At very high CBr4 partial pressures the morphology deteriorates and the growth rate decreases due to increasing etching effects. Traces of bromine are detected by SIMS only in layers grown at low temperature (6* 1015 cm-3 at 550°C and 2* 1014 cm-3 at 580°C). Carbon deactivation by hydrogen was observed in all layers. This passivation effect can be reduced by annealing in nitrogen for 15 minutes at 450°C. By photoluminescence mapping the excellent homogeneity of doping level (± 4% over entire 2inch wafer) was verified. These results demonstrate the suitability of CBr4 for growth of device structures like GaInP/GaAs HBTs.
