Abstract: The growth and characteristics of carbon-doped p-type InGaAs lattice matched to InP by gas source molecular beam epitaxy（GSMBE）werestudied,using carbon tetrabro mide（CBr₄）as a doping source.Under AsH₃ supply pressure 5.33×10⁴ Pa and growth temperature 500℃,ultr ahigh carbon-doped p-type InGaAs epi-lay er with hole concentration of 1×10²⁰/cm³ and room tempera-ture mobility of 45cm²/Vs are achieved.The effects of CBr₄ supply pressure,AsH₃ supply pressure and growth temperature on the composition,hole concentration and mobility of carbon-doped InGaAs epi-layers were investigated.The d ependence of hydrogen passivation e ffect on the growth condition was also studied.