Optimization of low temperature GaN buffer layers for halide vapor phase epitaxy growth of bulk GaN
2013 (English)In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 366, 61-66 p.Article in journal (Refereed) Published
We have studied growth and self-separation of bulk GaN on c-oriented Al2O3 using low temperature (LT) GaN buffer layers. By studying the X-ray diffraction (XRD) signature for the asymmetric and symmetric reflections versus the LT-GaN thickness and V/III precursor ratio, we observe that the peak width of the reflections is minimized using a LT buffer thickness of ∼100–300 nm. It was observed that the V/III precursor ratio has a strong influence on the morphology. In order to obtain a smooth morphology, the V/III precursor ratio has to be more than 17 during the growth of the buffer layer. By using an optimized LT buffer layer for growth of a 20 μm thick GaN layer, we obtain a XRD peak with a full width at half maximum of ∼400 and ∼250 arcs for (002) and (105) reflection planes, respectively, and with a dark pit density of ∼2.2×108 cm−2. For layers thicker than 1 mm, the GaN was spontaneously separated and by utilizing this process, thick free freestanding 2″ GaN substrates were manufactured.
Place, publisher, year, edition, pages
Elsevier, 2013. Vol. 366, 61-66 p.
Crystal morphology, Interfaces, Roughening, Growth from vapor, Hydride vapor phase epitaxy, Nitrides
IdentifiersURN: urn:nbn:se:liu:diva-90144DOI: 10.1016/j.jcrysgro.2012.12.016ISI: 000314824800013OAI: oai:DiVA.org:liu-90144DiVA: diva2:612149
Funding Agencies|Swedish Research Science Council||Swedish Energy Agency||2013-03-202013-03-202015-09-22