3C-SiC/Si template growth and atomic layer epitaxy of cubic GaN by RF-MBE

Abstract

Growth of 2 in cubic gallium nitride (c-GaN) film on a cubic silicon carbide on Si template (3C-SiC/Si) using Si (0 0 1) and Si(1 1 1) substrates was performed by using a radio frequency molecular beam epitaxy (RF-MBE) system, which was equipped with a jet nozzle. The 3C-SiC/Si template was prepared using alternating exposure of acetylene ( C 2 H 2 ) gas introduced by the jet nozzle under ultra high vacuum and Si molecular beam from a Si effusion cell. Very smooth 3C-SiC/Si templates with RMS roughness by atomic force microscopy of about 0.2–0.4 nm were grown here. Good crystal quality of low-temperature buffer (LTB) layer was obtained on a good 3C-SiC/Si template and confirmed through the observation of RHEED pattern. A grown c-GaN film's X-ray diffraction full-width at half-maximum of (0 0 2) peak was 13.2 arcmin ( 2 θ ) for a 544 nm-thick film. c-GaN was also grown using an atomic layer epitaxy (ALE) method. The ALE method proved to be necessary for a uniform and homogeneous atomic nitrogen flux under slightly Ga excess condition to grow the uniform c-GaN using rf-MBE.