HYDROGEN PASSIVATION OF SI DELTA-DOPED GAAS GROWN BY MOLECULAR-BEAM EPITAXY

Hydrogen passivation of Si delta-doped GaAs grown by molecular beam epitaxy is studied. Just as in uniformly Si-doped GaAs, exposure of the delta-doped material to a low frequency (30 kHz) hydrogen plasma at 250-degrees-C for 30 min deactivates the Si donors in the delta-spikes. For samples with Si doping of (1-6) X 10(18) cm-3, carrier concentration in the spikes decreased by nearly three orders of magnitude following hydrogenation. Secondary-ion mass spectrometric analysis of deuterated samples confirmed trapping of deuterium in the Si-doped spikes. Consistent with the deactivation of Si donors following hydrogenation, changes were observed in the near-band edge luminescence spectrum at 4.2 K, which showed in the hydrogenated sample the absence of Burstein-Moss shift that was observed in the as-grown sample. This hydrogen-induced passivation of Si donors in the delta-spikes can be of benefit in selectively deactivating donor atoms in device applications, and also provide a method for tailoring the hydrogen distribution in a epitaxial structure.