1.2 K SHUBNIKOV-DE HAAS MEASUREMENTS AND SELF-CONSISTENT CALCULATION OF SILICON SPREADING IN DELTA-DOPED AND SLAB-DOPED IN0.53GA0.47AS GROWN BY MOLECULAR-BEAM EPITAXY

Magnetotransport measurements are reported for In0.53Ga0.47As layers g rown by molecular beam epitaxy (MBE) at different substrate temperatur es (T-s) and either delta or slab-doped with Si. Multiple subband dens ities deduced from the Fourier analysis of 1.2 K Shubnikov-de Haas mea surements are compared with those derived from self-consistent calcula tions which include nonparabolicity and the doping profile width w(Si) as a fitting parameter. Significant spreading of the Si donors away f rom the doping plane is deduced for deposition at T-s approximate to 5 20 degrees C, while no measurable migration is inferred for T-s less t han or equal to 470 degrees C, leading to near-ideal delta-doping beha vior. Contrary to previous results [McElhinney et al., J. Cryst. Growt h 150, 266 (1995)], no evidence for amphoteric behavior has been found for Si areal densities up to 4 X 10(12) cm(-2). (C) 1996 American Ins titute of Physics.