Study of Substrate Induced Deep Level Defects in Bulk GaN Layers Grown by Molecular Beam Epitaxy Using Deep Level Transient Spectroscopy

In this paper we have investigated the substrate-induced deep level defects in bulk GaN layers grown on p-silicon by molecular beam epitaxy. Representative deep level transient spectroscopy (DLTS) performed on Au-GaN/Si/Al devices displayed only one electron trap E1 at 0.23 eV below the conduction band. Owing to out-diffusion mechanism; silicon diffuses into GaN layer from Si substrate maintained at 1050°C, E1 level is therefore, attributed to the silicon-related defect. This argument is supported by growth of SiC on Si substrate maintained at 1050°C in MBE chamber using fullerene as a single evaporation source.