Highly lattice mismatched InGaAs epitaxial layers on GaAs substrates were grown by low pressure MOCVD technique in order to improve surface morphology and interfacial quality. Four different structures were grown at a low temperature of 435°C. A thick In0.65Ga0.35As layer with a thickness of 1.6 μ m was grown directly on GaAs as a reference, while a similar InGaAs film was grown on a linearly graded compositional InxGA1-xAs buffer layer. Two additional In0.85Ga0.15As buffer layers were similarly grown on GaAs by embedding a thin metal film of either In or Ga at the heterointerface. Contrary to the reference sample and the sample with a graded buffer layer, the samples embedded with the metal films show no cross-hatch pattern and exhibit mirror-like surfaces. Cross-sectional high resolution TEM analysis for the samples with a metallic prelayer indicates that the misfit is relieved mainly by 90° perfect dislocations uniformly distributed near the interface. Hall effect measurements also suggest that the defect densities of these two samples are significantly lower than that of the reference sample.