Molecular beam epitaxial growth techniques for graded-composition InGaAlAs/InP alloys

Molecular beam epitaxy techniques used to grow uniform and graded-composition InGaAlAs alloys spanning the entire range from In/sub 0.53/Ga/sub 0.47/As to In/sub 0.52/Al/sub 0.48/As are reported. The compositional grading was achieved by flux modulation through effusion cell temperature control, under the supervision of a personal computer. It was found from double-crystal X-ray diffraction studies that maintaining the lattice-matching condition through a graded region is not significantly more difficult than achieving the initial lattice-matching conditions for the two ternary constituents of the graded quaternary alloy. The graded-layer growth procedure was extended to take into account thermal transients in the effusion cells and applied to the removal of shutter transients.<>