2012 journal article

Lateral epitaxial overgrowth of nitrogen polar GaN on smooth nitrogen polar GaN templates by metalorganic chemical vapor deposition

JOURNAL OF APPLIED PHYSICS, 112(11).

By: L. Hussey n, S. Mitaโ€‰*, J. Xie*, W. Guo n, C. Akouala n, J. Rajan n, I. Bryan n, R. Collazo nโ€‰, Z. Sitar n

co-author countries: United States of America ๐Ÿ‡บ๐Ÿ‡ธ
Source: Web Of Science
Added: August 6, 2018

Nitrogen (N)-polar GaN lateral epitaxial overgrowth (LEO), with a reduced dislocation density, is grown by metalorganic chemical vapor deposition on patterned, smooth N-polar templates. For LEO growth conditions identical to that of smooth N-polar GaN on sapphire, mask orientation dependent morphologies and faceting of the overgrowth regions are observed. N-polar LEO oriented along the ใ€ˆ1-100ใ€‰ direction exhibit flat sidewall morphologies while LEO oriented along the ใ€ˆ11-20ใ€‰ direction exhibit inclined sidewalls. A lateral to vertical growth ratio for the ใ€ˆ1-100ใ€‰ and ใ€ˆ11-20ใ€‰ oriented LEO was found to be โˆผ0.3 and 0.2, respectively. Transmission electron microscope observations reveal a reduction of dislocations of up to three orders of magnitude in the overgrowth regions from โˆผ1010 cmโˆ’2 in the template. Additionally, dislocation bending likely initiated from interfacial tension between the N-polar GaN and SiO2 mask is observed, resulting in a reduction of dislocation density to โˆผ109 cmโˆ’2 in the window region of re-growth.