Mismatched InGaAs/InP and InAlAs/InP heterostructures with high crystalline quality

Mismatched epitaxial layers of InxGa1−xAs and InyAl1−yAs were grown on InP by molecular beam epitaxy. Samples were characterized by high-resolution x-ray diffraction to assess layer quality as well as composition and strain. Measurement of epitaxial layer peak width is shown to be a sensitive, nondestructive means to judge the structural quality of a strained heterostructure. We find that for lattice mismatch of ±1% or less, the crystalline quality of epitaxial layers of InGaAs and InAlAs consistently remains high to thicknesses up to 3–9 times the Matthews–Blakeslee [J. Cryst. Growth 27, 118 (1974)] critical layer thickness. The findings are applied to the design and growth of high-performance mismatched InAlAs/InGaAs/InP heterostructure field-effect transistors.