Self‐consistent electronic subband structure calculations of periodic n‐type delta (δ)‐doped layers in Si and GaAs are performed within the local density‐functional approximation. The behavior of the energy levels, potential profiles, miniband occupancies, and Fermi level position with the variation of the dopant concentration ND and the spacing between the δ‐layers ds is examined for Si δ‐doping in GaAs and Sb δ‐doping in Si. The physical properties of these δ‐doping structures show a strong dependence on ds, reflecting a transition from isolated delta‐wells to superlattices as ds decreases. The crossover involving the change from a two‐dimensional to three‐dimensional behavior is discussed for both kinds of systems. © 1994 John Wiley & Sons, Inc.