Heavy doping of GaAs and AlGaAs with silicon by molecular beam epitaxy

Heavy Si doping of GaAs and AlGaAs grown by molecular beam epitaxy has been studied. By using a slow growth rate of 1000 Å/h, the electron concentration obtained for GaAs was 1.1×1019 cm -3, which is higher than the previously reported limit of 5×1018 cm-3. The accumulation of excess Si near the surfaces of GaAs and AlGaAs has been identified by secondary ion mass spectroscopy. A Si-induced 3×2 surface structure has been observed, and the influence of arsenic to gallium flux ratio on the surface morphology is discussed. Photoluminescence spectra of the doped layers are presented.