The Raman scattering by longitudinal‐optical (LO) phonon‐plasmon‐coupled (LOPC) mode in carbon‐dopedp‐type InGaAs with indium compositionx≊0.3 and hole concentration from 1017to 1019cm−3grown by metalorganic molecular beam epitaxy was studied experimentally. Only one LOPC mode appears between the GaAs‐like and InAs‐like LO modes was observed. The peak position of the LOPC mode is near the GaAs‐like transverse‐optical mode frequency and is insensitive to the hole concentration. The linewidth and intensity of the LOPC mode are dependent strongly on the carrier concentration, while the two LO modes decrease and become invisible under the high doping level. It was shown that the plasmon damping effect plays a dominant role in Raman scattering by LOPC mode for thep‐type InGaAs. ©1995 American Institute of Physics.