Diffusivity of arsenic interstitials in GaAs studied by sulfur in-diffusion

Sulfur in-diffusion, which is governed by the kick-out mechanism, is a suit able tool to study the diffusion on the arsenic sublattice of GaAs. Sulfur diffuses for higher surface concentrations under non-equilibrium conditions of arsenic self-interstitials (I-As) The formation of extrinsic dislocatio n loops has been observed. The loop formation increases the concentration o f Ga vacancies, which form complexes with S donors. The presence of such co mplexes has been investigated by cathodoluminescence, positron annihilation , and electrochemical capacity-voltage profiling. Taking into account the c oncentration of As interstitials agglomerated in faulted loops, the analysi s of the sulfur profile can provide both the diffusion constant and the equ ilibrium concentration of I-As (C) 1999 Elsevier Science B.V. All rights re served.