Be-doped p(+)-GaAs epitaxial thin layers were grown on (0 0 1)-oriented GaAs substrates by intermittent supply of arsine, triethylgallium and Bismethylcyclopentadienyl-beryllium [Be(MeCP)(2)] in an ultra-high vacuum at low growth temperature 260-375degreesC. By changing the gas injection sequences and supply time, the surface stoichiometry before the introduction of impurity precursor is controlled. Heavily Be-doped p+-GaAs grown at 290degreesC shows high carrier concentration up to 8 x 10(19) cm(-3) with Hall mobility of 42 cm(2) V-1 s(-1) at nominal room temperature. It is shown that the incorporation of Be is extremely enhanced when Be(MeCP)(2) is exposed on the gallium-stabilized surface. In view of the surface stoichiometry control, Be doping mechanism is discussed on the basis of rate law of surface chemical reactions. (C) 2003 Elsevier B.V. All rights reserved.