In<sub>0.82</sub>Ga<sub>0.18</sub>As was grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) on InP substrates
with two-step growth technique. Three groups sample with different buffer growth conditions were analyzed by Raman
scattering. The intensity of GaAs-like LO phonon of Raman scattering, the frequency shift of the GaAs-like LO phonon
and asymmetry ratio [symbol] of GaAs-like LO phonon of samples were characterized the optical property of In<sub>0.82</sub>Ga<sub>0.18</sub>As epilayer, respectively. The results of experiments showed that the optimum buffer In content was 0.82, the optimum
buffer thickness was about 100 nm, and the optimum buffer growth temperature was about 450 °C.