Influence of Al-flux on the growth of AlN/GaN/AlN films on Si (1Â 1Â 1) substrate by MBE

The effect of the Al flux on the crystal quality of AlN/GaN/AlN heterostructures grown on Si (1 1 1) substrates by solid source molecular beam epitaxy, using a 13.56 MHz RF nitrogen source, was investigated. The thickness of 69.94 nm is obtained for good growth conditions giving the comparable FWHM of the XRD-rocking curve of 0.46° (27.6 arcmin) when compared with other samples and previous reports. We found that the AlN sample grown under low Al-flux has produced a good structural quality and low compressive strain value compared to the sample grown under high Al-fluxes.