WIRE-LIKE INCORPORATION OF DOPANT ATOMS DURING MBE GROWTH ON VICINAL GAAS(001) SURFACES

The ordered incorporation of dopant atoms by combining lattice step growth on vicinal GaAs(001) surfaces and Si delta(delta)-doping has been studied by real-time reflection high-energy electron diffraction (RHEED) measurements. For Si deposition on 2-degrees toward the (111)Ga plane misoriented surfaces and 0.4-degrees toward the (11BAR1)As plane misoriented surfaces it is shown that the Si atoms arrange themselves preferentially along the step edges in a (3 x 2) structure consisting of an ordered array of Si dimers. For Si concentrations not exceeding substantially the amount expected to be attached at the step edge the GaAs growth can be continued at reduced substrate temperature without adverse effects on the growth front. By pulsed delta-doping an unusual high concentration of Si atoms can be incorporated as donors on Ga sites.