Reflection high energy electron diffraction intensity behavior during homoepitaxial molecular beam epitaxy growth of GaAs and implications for growth kinetics and mechanisms

Abstract

The dynamic behavior of GaAs surfaces during and after growth by MBE has been probed by detailed measurements of the specular beam intensity in RHEED patterns from the surfaces. The damping of the intensity oscillations observed after growth has commenced is shown to be a strong function of arsenic pressure with high pressure causing strong damping and rough growth fronts. The specular beam intensity after steady-state growth has been interrupted shows first an initial fast increase with the largest increase occurring at low arsenic pressure, and then a slow recovery to its equilibrium no-growth intensity at a rate that increases with arsenic pressure. Measurements of the intensity recovery after short growths on an equilibrated no-growth surface provide new information about the growth front behavior during the first few monolayers of growth. The surface recovers in the shortest time after deposition of either a small fraction of a monolayer or slightly more than an integer number of monolayers. Recovery is slow after deposition of half a monolayer due to the resulting high step density. Surprisingly, recovery is slowest after deposition of 1.0 monolayer, indicating that such surfaces are very different from the equilibrium no-growth surface.