DELTA-DOPING OF GAAS AND AL0.33GA0.67AS WITH SN, SI AND BE - A COMPARATIVE-STUDY

We have performed a study of the contributions of segregation, diffusion and aggregation to the broadening of delta-doped planes of Sn, Si and Be in GaAs and Al0.33Ga0.67As. Sn planes are severely broadened by all three processes, but sharp spikes of Si and Be can be obtained in both host materials for sheet densities below 10(13) cm-2 and growth temperatures of 500-degrees-C or less. At higher temperatures or densities, segregation or concentration-dependent rapid diffusion may occur, causing significant spreading even during growth. Co-deposition of Si and Be dramatically reduces this broadening, and various mechanisms are considered to explain these effects.