Abstract
The effects of hydrogen plasma passivation on optical and electrical properties of metalorganic chemical vapor deposition (MOCVD) grown GaAs-on-Si epilayers have been studied. The intensity of photoluminescence (PL) was enhanced as much as four times by H plasma passivation followed by annealing in AsH3 ambient at 400°C. The minority carrier lifetime was also increased effectively by the passivation process. Compared to the results of deep-level transient spectra (DLTS) measurements, the improvement in optical properties appears to be a result of the passivation of the dislocation-associated deep defects in the GaAs-on-Si epilayers by H plasma passivation. The passivation effects persist even after the annealing process at 400°C, which suggests that the H plasma passivation may be a useful method for improving the properties of the GaAs-on-Si-based devices.