Free-standing (0002)-oriented GaN substrates (φ = 2”) were coated with 200 nm of ZnO and used as templates for the growth of GaN thin films. SEM and AFM revealed that such GaN layers had a relatively homogenous surface morphology with an RMS roughness (5 μm x 5 μm) of less than 4nm. XRD studies revealed strained ZnO growth on the GaN substrate and the reproduction of the substrate rocking curve for the GaN overlayers after only a hundred nm of growth, thus indicating that the GaN films had superior crystallographic quality compared to those grown on sapphire or ZnO/sapphire substrates. Quarter-wafer areas of GaN were removed from the GaN substrate (by selective chemical etching away of the ZnO interlayer). The expensive GaN substrates were then reclaimed/reused (without the need for polishing) for a second cycle of ZnO and GaN growth, which gave similar XRD, SEM, CL and AFM results to the first cycle.

Date Published: 2 April 2014
PDF: 8 pages
Proc. SPIE 8987, Oxide-based Materials and Devices V, 898719 (2 April 2014); doi: 10.1117/12.2043704

Published in SPIE Proceedings Vol. 8987:
Oxide-based Materials and Devices V
Ferechteh H. Teherani; David C. Look; David J. Rogers, Editor(s)