VOID FORMATION, ELECTRICAL ACTIVATION, AND LAYER INTERMIXING IN SI-IMPLANTED GAAS ALGAAS SUPERLATTICES

Direct experimental evidence is presented for the correlation between void formation, dopant electrical activation, and layer intermixing in GaAs/AlGaAs superlattices (SLs). Maximum layer intermixing is observed in the regions of maximum carrier concentration and no or little void formation in Si-implanted and annealed SLs. In SLs implanted at room temperature, Si activation and layer intermixing enhancement are severely inhibited in the near-surface region where voids are formed. However, when implantation is carried out at 250°C, both the suppression of Si activation and layer intermixing enhancement in the near-surface region are reduced, concurrent with a decrease in void density.