Growth and evaluation of gallium nitride on silicon(111) substrates using electron cyclotron resonance plasma-assisted molecular beam epitaxy

GaN is one of the most important targets among the wide-band-gap materials used in optical devices. In 1993 the first high brightness blue light emitting diodes and violet lasers diodes were developed based on III-V nitride. Those devices were a result of the successful growth of GaN of sufficient quality onto a sapphire substrate. Si(111) is considered to be an alternative substrate for GaN growth because the availability of wide-band-gap light emitters and detectors on Si would be of significant benefit to nitrides and potentially have a big impact on Si integrated circuit technology as well.; In this study, Si(111) substrates with an AlN buffer layer are used for Mg-doped wurtzite GaN growth using electron cyclotron resonance plasma-assisted molecular beam epitaxy. The film qualities strongly depend on the plasma conditions during growth, i.e., the ion exposure on the growth surface strongly affects the photoluminescence intensity. Plasma diagnostics and a model of plasma drift from the ECR region are applied to interpret the relationship between the intensity of photoluminescence associated with the Mg acceptor level in GaN and the plasma parameters during growth. Furthermore, bias effects on GaN films are clarified.; This research concludes that Mg-doped GaN grown on Si(111) by ECR plasma-assisted molecular beam epitaxy exhibits a sufficiently high quality of films. The minimum RF power applied to the ECR system gives the minimum ion drift toward the growth surface resulting in the minimum disorder of the GaN film. Mg dopant in a GaN film supplies acceptor levels that form donor-acceptor pairs; a variation of acceptor levels measured by photoelectron spectroscopy corresponds to the peak width of photoluminescence intensities.