Effect of growth conditions at MOCVD on thickness uniformity of GaInAsP epilayers obtained on InP

Ga1-xInxAsyP1−y epitaxial layers with compositions x = 0.77 − 0.87, y = 0.07 − 0.42 and thicknesses 620 − 850 nm were grown by MOCVD method on InP substrates. Temperature, pressure and gas mixture composition were held constant during growth procedure. Secondary-ion mass spectrometry showed change of V-group elements composition y through epilayers thicknesses by value Δy up to 0.08. Reducing Δy value down to 0.01 − 0.02 was achieved by optimizing the composition of gas mixture to reduce lattice mismatch between the layer and the substrate. The obtained data allow us to conclude that the deformations arising due to lattice mismatch between the forming layer and the growth surface result in varying the content of V-group elements through epilayer thickness.