Microscopic behavior of silicon in silicon delta-doped layer in GaAs.

Silicon δ-doped layers in GaAs have been studied using scanning tunneling microscopy and scanning tunneling spectroscopy on cleaved (110) surfaces. The samples were grown using molecular beam epitaxy with two growth temperatures: 480 and 580 °C. The concentration of the δ-doped layer was 0.03 monolayer. We show that, as in the case of bulk doping, the silicon has an amphoteric character: both Si[sub Ga] and Si[sub As] are observed at 480 °C and donors are formed before acceptors. At 580 °C, the spatial repartition of silicon evidences the segregation of silicon. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]