Effects of source gas molecules on N–H- and N–D-related defect formations in GaAsN grown by chemical beam epitaxy

The formation mechanism of N–H-related defects in GaAsN grown by chemical beam epitaxy (CBE) is studied on the basis of the isotope effects on the local vibration modes (LVMs) originating from N–H. When deuterated monomethylhydrazine (MMHy) is used as the N source, LVM signals from the nitrogen–deuterium bond (N–D) are obtained. However, there are still N–H peaks in the IR absorption spectra, which have intensities similar to those of N–D peaks. When the film is grown with deuterated triethylgallium (TEGa), there are no N–D peaks. The peak intensity at 2952 cm −1 increases with increasing tris(dimethylamino)arsenic (TDMAAs) flow rate, and that at 3098 cm −1 is almost constant regardless of the flow rate. These results indicate that H atoms in the N–H-related defects originate from H directly bonded to N in MMHy and CH 3 in MMHy and/or H in TDMAAs, not from TEGa.