Passivation of Si donors and D X centers in AlGaAs by hydrogen plasma exposure

Abstract

The effect of hydrogen plasma exposure upon shallow donors and DX centers in silicon‐doped AlGaAs has been investigated by deep level transient spectroscopy and capacitance versus voltage measurements. Following exposure to a hydrogen plasma for 30 min at 250 °C, the shallow level and DX center activity are reduced by an order of magnitude throughout a 1.6‐μm‐thick layer of molecular beam epitaxially grown AlGaAs. Isochronal annealing studies showed that both the shallow donor and DX center electrical activity recover together at about 400 °C. The shallow donor recovery mimics the behavior of donors in GaAs and has an activation energy of 2.0 eV. The DX center recovery shows a distribution of activation energies centered at 2.1 eV with a full width at half‐maximum of 0.25 eV. The hydrogen passivation chemistry of DX centers and shallow donors support models in which isolated Si impurities give rise to both DX behavior and shallow levels.