RHEED oscillation studies of MBE growth kinetics and lattice mismatch strain-induced effects during InGaAs growth on GaAs(100)

Abstract

We present the first report of RHEED intensity changes and recovery as a function of monolayer and submonolayer MBE depositions of In_xGa_1−xAs (x≤0≤0.5) on GaAs(100) substrates. The influence of the lattice mismatch‐induced strain on the growth mechanisms and the incorporation behavior of In and Ga is suggested by new and In concentration dependent effects in the RHEED intensity waveform behavior during growth. The monolayer oscillation period is determined by the combined In and Ga fluxes. The initial growth of InGaAs on GaAs(100) is planar, but after an amount of deposition depending upon InAs content and growth conditions, a sudden change from a streaked reflection pattern to a spotty transmission pattern is observed indicating formation of 3D islands. The film thickness at which this transition occurs is strongly influenced by the step density of the GaAs surface when InGaAs growth is initiated. We have examined the recovery behavior of the specular spot intensity after the growth of 0.1 to 15 monolayers of GaAs on an annealed metal‐stabilized GaAs(100) surface. In this experiment, the RHEED intensity has dropped from its initial (no‐growth) value and, after termination of growth, it slowly recovers to its steady‐state value. We report RHEED intensity recovery rates as a function of the number of monolayers of GaAs deposited and compare them to recovery rates after steady‐state growth has been reached. The recovery rate is a strong function of the completeness of the surface when growth is stopped.