A study of the composition gradient of GaInAsP layers formed on InP by vapor-phase epitaxy

Gradual variation of the content y of Group-V components by $\Delta y$ of up to 0.08 across the thickness (600 – 850 nm) of an epitaxial layer has been observed for Ga$_{1-x}$In$_{x}$As$_{y}$P$_{1-y}$ solid solutions ($x$ = 0.86, $y$ = 0.07 – 0.42) produced on InP by metal-organic vapor-phase epitaxy under lowered pressure, although the composition of the gas mixture, temperature, and pressure were maintained invariable in the course of the growth process. For different gas mixture compositions, the value of $\Delta y$ and the manner of its variation were different. An analysis of the data obtained demonstrated that $\Delta y$ is due to the deformations that appear in a growing layer because of the lattice mismatch with the substrate.