MOCVD Growth of GaN on Sapphire Using a Ga2O3 Interlayer

Abstract

Metalorganic chemical vapor deposition (MOCVD) was used to grow crystalline GaN on a Ga2O3 interlayer deposited by pulsed laser deposition. The Ga2O3 interlayer situated between undoped GaN (u-GaN) and sapphire can be etched out during the chemical lift-off process. A ((2) over bar 01) oriented beta-Ga2O3 thin film was first deposited on the sapphire; this was followed by u-GaN growth via MOCVD carried out in an N-2 atmosphere to prevent the decomposition of Ga2O3. Using transmission electron microscopy (TEM), the orientation relationship was observed to be GaN[11 (2) over bar0] parallel to Ga2O3[010] where the lattice mismatch between the two materials was 8.5%. The full width at half maximums of the x-ray rocking curve at the GaN (0002) plane and of the photoluminescence spectrum measured from GaN/Ga2O3/sapphire were 1444 arcsec and 8.3 nm, respectively; these were almost identical to the measured values for GaN/sapphire fabricated in an N-2 environment. It was concluded that the growth atmosphere played a more important role in determining the crystallinity of u-GaN than the Ga2O3 thin film underneath. Finally, an InGaN light-emitting diode structure was successfully fabricated on the GaN/Ga2O3/sapphire. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.073111jes] All rights reserved.