Hexagonal GaN Epitaxial Growth on Si(111) by a Vacuum Reaction Method

Abstract

In this paper, a single crystalline GaN grown on Si(111) is reported using a GaN buffer layer by a simple vacuum reaction method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence measurement (PL), Hall measurement and secondary ion mass spectroscopy (SIMS) results indicate that the single crystalline hexagonal GaN was successfully grown on the microcrystalline GaN buffer layers on Si(111) substrate. The surface of the GaN films is flat and crack-free. A pronounced GaN (0002) peak appears in the XRD pattern. The full width at half-maximum (FWHM) of the double-crystal X-ray rocking curve (DCXRC) for (0002) diffraction from the GaN epilayer is 30 arcmin. The TEM reveals that a 10 nm GaN buffer layer in the microcrystalline state exists between the Si substrate and the epilayer, which dissipates most of the stress energy. The PL spectrum shows that the GaN epilayer emits light at the wavelength of 365 nm with an FWHM of 8 nm (74.6 meV). The unintentionally doped films were n-type with a carrier concentration of 1.75 x 10 18 /cm 3 and an electron mobility of 142 cm 3 /Vs. The growth technique described was simple but very powerful for growing single crystalline GaN films on Si substrates.