ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Silicon carbide (SiC) has become the substrate of choice for III-N epilayers applied toelectronic devices due to the lack of a native III-N substrate. This is particularly true for highpower applications, since the thermal conductivity of the substrate enhances device performance.Although the GaN lattice match is slightly better for SiC than for sapphire, the dislocation densitiesthat result are still very high (generally in the high 108 cm-2 range) and often deleterious to deviceperformance. Screw-component dislocations are especially critical since they serve as leakagepaths in vertically conducting III-N devices.In this paper efforts to reduce the extended defect density in III-N films grown on SiC will bereviewed. Details on recent efforts to use step-free SiC mesa surfaces arrayed on commercial 4HSiCsubstrates will then be highlighted showing dramatic reductions in extended defect densitiesand the virtual elimination of critical defects for vertically conducting devices. In theseexperiments, SiC surfaces that are homoepitaxially grown step-free or of very low step density havebeen used as growth templates for thin (〈3 μm) GaN films deposited on a novel 1000 Å AlNnucleation layer characterized by a total dislocation density two orders of magnitude lower than theprevious state-of-the-art, and with no evidence of screw-component dislocations
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/14/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.527-529.1483.pdf
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