Passivation and generation of deep level defects in hydrogenated n-GaAs (Si)

Bulk n‐type GaAs wafers (Si doped) have been exposed to a capacitively coupled rf hydrogen plasma at different power densities ranging from 0.01 to 0.2 W/cm2 at 260 °C. The electronic properties of these layers have been investigated by capacitance‐voltage experiments and deep level transient spectroscopy. Besides the neutralization of the silicon donors by the in‐diffused hydrogen atoms, we observe a modification of the deep level transient spectroscopy (DLTS) spectra after hydrogenation. For rf power densities lower than 0.1 W/cm2, the deep levels present in the region of the starting material explored by DLTS are passivated. The absence of electronic states associated with the silicon‐hydrogen complexes in the neutralized donor region indicates that these complexes are either electrically inactive or deeply located in the energy band gap. For rf power densities higher than 0.1 W/cm2, two new deep electronic states appear at 0.41 and 0.55 eV below the conduction band. These levels are the signature of a...