Arsenic precipitation from thin surface layers of lowhyphen;temperature grown GaAs

摘要

Arsenic precipitation from a thin, 100hyphen;nm surface layer of GaAs grown at low temperature (LT) by molecular beam epitaxy is investigated. The precipitate depth distribution is examined for different rapid thermal annealing cycles. It is found that the precipitate distribution can tail a long distance into the underlying stoichiometric GaAs layer, depending on the peak annealing temperature. The distribution for an 800thinsp;deg;C anneal is virtually unaffected by a prior low temperature lsquo;lsquo;soakrsquo;rsquo; at 600thinsp;deg;C, thus showing that the precipitation is insensitive to the initial point defect concentrations in this temperature range. The relevance of these results to the precipitation process and to the use of thin LT layers in device applications is discussed. copy;1996 American Institute of Physics.