Preliminary Characterization of GaN MBE Epitaxial Layers Grown on Nanoporous 6H-SiC Substrates

We report on the growth and quality of plasma enhanced molecular beam epitaxy (PEMBE) of an n-GaN layer grown on a 6H-SiC substrate, which was prepared to be half nanoporous. A layer of nanoporous SiC was fabricated on a half section of n-type, on-axis (0001)Si face 41 mm commercial wafer by surface anodization. Following H-plasma surface cleaning andin-situ thermal annealing, a 0.7µm thick silicon doped GaN film was deposited at a growth rate of 0.35µm/hr. Substrate temperature during GaN growth was 709oC with a chamber pressure of 1.9 × 10−5Torr. Results of X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) characterization suggest improved chemical quality of the film grown on the nanoporous section. Photoluminescence (PL) data indicate greatly reduced nonradiative recombination in the epi layer grown on the nanoporous as compared to the control surface.