SIMS Study of Si–Be Co-doping Effects for Suppression of Compositional Disordering in AlGaAs–GaAs Superlattices

Abstract
We have studied the Si–Be co-doping effect for the suppression of the compositional disordering of AlGaAs–GaAs superlattices (SLs) by SIMS. The Si–Be co-doping is found to suppress the fast Si diffusion which is ascribed to the formation of (SiIII–SiV) pairs. The possible mechanism is that the formation of (BeIII–SiIII) pairs prevents that of (SiIII–SiV) pairs. The suppression of the Si fast diffusion impedes the SL disordering. The threshold concentration of Be required to suppress the SL (300 Å periodicity) disordering is around 2×1018 cm-3 in the case of 1.5×1019 cm-3 Si concentration.