SiC rapid thermal carbonization of the (111)Si semiconductor-on-insulator structure and subsequent metalorganic chemical vapor deposition of GaN

Abstract

Si (111) semiconductor-on-insulator (SOI) structures have been converted to SiC by carbonization of the thin (<100 nm) Si layer using rapid thermal chemical vapor deposition with mixtures of propane and H2 at atmospheric pressure. Carbonization temperatures around 1225–1250 °C produced SiC films with optimum structural properties. X-ray diffraction (XRD) reveals a single SiC peak at 2θ=35.7° corresponding to the (111) reflection, with an uncorrected full width at half-maximum (FWHM) of ∼0.24°. Infrared spectroscopy of SiC SOI structures obtained under optimum carbonization conditions exhibited a sharp absorbtion peak produced by the Si–C bond at 795 cm−1, with FWHM=22–25 cm−1. Metalorganic chemical vapor deposition growth of GaN on the (111) SiC SOI was carried out with trimethylgallium and NH3 precursors at 1000 °C. XRD indicates highly oriented hexagonal GaN, with FWHM of the (0002) peak of ∼0.15°. The 300 °K photoluminescence (PL) spectrum of GaN films exhibits a strong near band-edge peak (at λp∼371 nm, with FWHM=100–150 meV) and weak yellow emission. Under low power excitation, the 370 nm PL emission from the GaN/SiC SOI structure displays an emission intensity ∼10× higher than that of equivalent GaN films grown on sapphire.