Improved Crystalline Quality of AlN by Epitaxial Lateral Overgrowth Using Two-Phase Growth Method for Deep-Ultraviolet Stimulated Emission

We report on the maskless epitaxial lateral overgrowth (ELOG) of the AlN layer on trench-patterned AlN/sapphire templates by metal-organic chemical vapor deposition (MOCVD). With a two-phase growth of different V/III ratio at a relatively low growth temperature of 1250 °C, up t...

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Main Authors: Xiang Chen, Jianchang Yan, Yun Zhang, Yingdong Tian, Yanan Guo, Shuo Zhang, Tongbo Wei, Junxi Wang, Jinmin Li
Format: Article
Language:English
Published: IEEE 2016-01-01
Series:IEEE Photonics Journal
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Online Access:https://ieeexplore.ieee.org/document/7582371/
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Summary:We report on the maskless epitaxial lateral overgrowth (ELOG) of the AlN layer on trench-patterned AlN/sapphire templates by metal-organic chemical vapor deposition (MOCVD). With a two-phase growth of different V/III ratio at a relatively low growth temperature of 1250&#x00A0;&#x00B0;C, up to a 7.3-&#x03BC;m-thick high-quality crack-free AlN film with a threading dislocation density of 8 &#x00D7; 10<sup>8</sup>&#x00A0;cm<sup>&#x2013;2</sup> was obtained. Compared with the 0.9-&#x03BC;m AlN film grown on a planar sapphire substrate, the ELOG-AlN film has a lower dislocation density and a much better strain state, regardless of its 7.3-&#x03BC;m thickness. Compared with the single low V/III ratio growth, the two-phase growth method can lead to a coherent coalescence at the second growth stage and hence suppress new dislocations generating at the coalescence fronts. Stimulated emission was observed from Al(Ga)N multi-quantum-wells laser grown on the ELOG-AlN template with low dislocation density. The deep-ultraviolet laser (DUV) on these templates exhibited lasing at 263.3&#x00A0;nm with the spectral linewidth of 1.29&#x00A0;nm and threshold pumping power density of 2.7 MW/cm<sup>2</sup> at room temperature.
ISSN:1943-0655