Vertical exchange reaction in (Ga,In)As during migration-enhanced epitaxy

We formulate a kinetic description of the vertical exchange reaction in which Ga replaces In during migration enhanced epitaxy of GaAs on InAs. Considering the Ga deposition rate R to be finite rather than infinite, as was done previously, leads to a reinterpretation of experimental results. The kinetic coefficient k as found by comparison with the In concentration profile determined by secondary ion mass spectroscopy is found to be 25% greater at 500 degrees C, cycle time of 5 s and R = 1/2 s(-1) than that found earlier. The probability of an In atom being replaced by a newly deposited Ga atom, which depends on the details of the Ga deposition schedule, is determined and found to be identical, 98%, for these conditions to that found earlier. (C) 1997 American Institute of Physics.