Broadening of the Si doping layer in planar-doped GaAs in the limit of high concentrations

Abstract

Abstract A series of samples of GaAs planar doped with Si, grown by MBE at low substrate temperatures and with different doping concentrations, is investigated. A comparison of Shubnikov-de Haas measurements and self-consistent numerical calculations shows that a broadening of the doped region occurs in spite of the low growth temperature. The broadening occurs via segregation of the Si impurities with the growth surface when the solid solubility limit of Si in GaAs is exceeded. For the growth conditions used this limit is determined to be (2.1 ± 0.2) × 1019 cm−3. At high doping densities an intrinsic compensation mechanism becomes active, limiting the concentration of conduction electrons.