TBP (tertiarybutylphosphine), a relatively new material for phosphorus, has been studied with EDMIn (ethyldimethylindium) as an indium source for the growth of InP by MOVPE (metalorganic vapor phase epitaxy). Mirror smooth and good crystalline InP layers were obtained at 500-600℃ with the TBP/EDMIn molar ratio as low as 21. The deposited InP layers are all n-type with the electron concentration in the range of (5-10)×10(16) cm-3, which is a lot higher than those from PH3. This high concentration is due presumably to the high concentration of donor impurities in TBP. And it has been found that the formation of adduct occurs between EDMIn and TBP at room temperature when the partial pressure of EDMIn in the reactant mixture is above 1×10(-2) Torr. The high concentration of impurities in TBP and the adduct formation between EDMIn and TBP are major obstacles in replacing PH3 and TMIn for the growth of device quality InP layers.