Solid-solubility limits of Be in molecular beam epitaxy grown Al(x)Ga(1-x)As layers and short-period superlattices

The redistribution of Be in highly doped Al(x)Ga(1-x)As layers and Al(x)Ga(1-x) As/AlAs(GaAs) short period superlattices (SPSL) during molecular beam epitaxy was investigated by secondary ion mass spectrometry (SIMS) depth profiling. Be outdiffuses significantly from these layers and, additionally, segregates in growth direction. Conversely, Be is depleted and incorporated only up to a solid-solubility limit depending on the Al content. SPSLs with shorter period are disordered and show the solid-solubility limits of homogeneous Al(x)Ga(1-x)As layers with the same average composition. Be solid-solubility limits in Al(x)Ga(1-x)As layers covering the whole range from GaAs to AlAs are derived from the SIMS depth profiles.