Epitaxial growth of stoichiometric (100) GaAs at 75 °C

Abstract

Molecular beam epitaxial growth of InAs/AlGaAsSb deep quantum well structures on GaAs substratesSurface evolution on vicinal GaAs(001) surfaces in the transition range from two-dimensional to step-flow growth Stoichiometric single crystal GaAs is grown at 75°C by a migration-enhanced-epitaxy ͑MEE͒ technique. The stoichiometry of the GaAs films can be controlled by adjusting the arsenic monolayer deposition time. For Ga-rich compositions, epitaxy breaks down and polycrystalline GaAs results. For stoichiometric GaAs, and As-rich compositions, epitaxy proceeds and specular stoichiometric films can be grown to significant thicknesses. Reflection high-energy electron diffraction patterns indicated some surface roughness that increased for compositions closer to those which were Ga rich. This work suggests that low-temperature growth by MEE results in limited-thickness-epitaxy ͑LTE͒ behavior for GaAs that is very different from low-temperature growth by conventional molecular beam epitaxy. The results of this work indicate the importance of stoichiometry, surface roughening, and surface diffusion phenomena in determining regimes where epitaxy occurs at low temperature. A maximum LTE epitaxial thickness of 300 nm was obtained at 75°C.

Optoelectronic device performance on reduced threading dislocation density GaAs/Si

“…The wafers were slowly outgassed up to 450 K and then heated from 450 to 825 K under an As 4 overpressure so as to obtain a naturally self-limiting 28 atomic monolayer of arsenic on the silicon surface ͑''arsenic passivation''͒ after the protective hydrogen-passivation layer desorbs at roughly 800 K. 27 The arsenic-passivated wafer was then cooled and 1 h was allowed for steady-state temperature to be established. Stoichiometric GaAs was deposited at 348 K to a thickness of h m by a migration-enhanced epitaxy ͑MEE͒ technique; 29 the slow average deposition rate ͑MEE͒ of approximately 0.015 nm/s, contributes to the retention of epitaxy at such a low growth temperature. The monolithic thickness, h m , for the GaAs/Si case is empirically observed and can be calculated to be 80 nm using a morphology-conversion analysis.…”