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 (Si III –Si V ) pairs. The possible mechanism is that the formation of (Be III –Si III ) pairs prevents that of (Si III –Si V ) 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 2×10 18 cm -3 in the case of 1.5×10 19 cm -3 Si concentration.