The growth of heavily carbon doped indium gallium arsenide lattice-matched to indium phosphide grown by low pressure metal organic chemical vapor deposition (LP-MOCVD) using all methyl metalorganic sources and liquid CCl4 is examined. The impact of growth conditions on conduction type and alloy composition of InGaAs were studied. The effect of thermal annealing conditions on the hole concentration and mobility of C-InGaAs was investigated and carbon displacement from group III site to arsenic site as well as reduced hydrogen passivation is suggested as a possible mechanism for the significant increase of hole concentration upon annealing.