Residual strains in heteroepitaxial III-V semiconductor films on Si(100) substrates

Abstract

A systematic study has been made of residual strains in heteroepitaxial GaP, GaAs, and InP layers on Si(100) grown by organometallic vapor phase epitaxy. For GaP films, the strain parallel to the interface changes from compressive to tensile for film thicknesses between 0.7 and ∼1.5 μm, showing that the dominant force for strains changes from a lattice mismatch to a discrepancy of the thermal expansion coefficient between GaP and Si. All GaAs and InP films examined (1–5 μm thick) have a tensile strain almost independent of the thickness. The magnitudes of the residual strains are in the order εGaAS>εGaP>εInP. The low strain in GaP films is due to the compensation of thermally induced tensile strain by a compressive strain, which is induced during the accommodation of lattice mismatch at the growth temperature. For GaAs and InP films, it is concluded that a fraction of the thermally induced tensile strain is accommodated during the cooling process by a reconfiguration of misfit dislocations at the interface. The level of residual strain in InP films, which is the lowest, is suggested to be due to the misfit dislocation rearrangement which can occur at a relatively low temperature (∼250 °C) in this material, as well as the low growth temperature and the small thermal expansion coefficient difference between InP and Si(100).