Metalorganic chemical vapor deposition growth of Ga-rich ( x > 0.5) Ga xIn 1− xP on GaAs

Abstract

Epitaxial layers of Ga x In 1− x P (0.5 ≦ x ≦ 1.0) were grown on GaAs substrates by metalorganic chemical vapor deposition (MOCVD), using TMI (trimethylindium), TMG (trimethylgallium), TEG (triethylgallium), and phosphine. Despite the lattice mismatch between the epitaxial layer and the substrate, specular surfaces were obtained at high growth temperature (770°C) and a long interval time (τ = 60 s), where τ is defined as the period between column V gas switching (AsH 3 → PH 3) and column III source injection. It is also observed that the surface morphology depends on the Ga precursors. When TEG is used as a Ga precursor, specular surfaces are obtained for 0.77 ≦ x ≦ 1.00, where x is the solid composition ratio of Ga x In 1− x P. When TMG is used as a Ga precursor, specular surfaces are obtained for 0.81 ≦ x ≦ 0.95. By measuring with the X-ray double-crystal method, it is observed that the rocking curve around the GaAs substrate was split into two peaks due to the GaAsP film formed during the interval time. The FWHM (full width at half maximum) of Ga x In 1− x P against x showed a peak of 800 arc sec at x = 0.8.