Spatial resolution of the capacitance-voltage profiling technique on semiconductors with quantum confinement

The spatial resolution of the capacitance-voltage profiling technique on semiconductors with one-dimensional quantum confinement is shown to be given by the spatial extent of the wave function. The Debye length limitation does not apply. Capacitance-voltage profiles on δ-doped GaAs of density 4–4.5×1012 cm−2 exhibit widths of 20 and 48 Å for p- and n-type impurities, respectively. The profiles agree with the theoretical resolution function and with Be and Si profiles measured by secondary-ion mass spectroscopy. It is further shown that the saturation of the free-carrier density of highly Si δ-doped GaAs grown by molecular beam epitaxy is due to inactive Si impurities