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Proceedings Paper

Improved crystalline quality of nonpolar a-plane GaN grown on r-plane patterned sapphire substrate (Conference Presentation)
Author(s): Shunya Otsuki; Daiki Jinno; Hisayoshi Daicho; Satoshi Kamiyama; Tetsuya Takeuchi; Motoaki Iwaya; Isamu Akasaki

Paper Abstract

Nonpolar a-plane GaN (a-GaN) grown on r-plane sapphire substrate is one of the promising materials for eliminating an internal field in III-nitride devices. Thus, a high performance light-emitting diode can be expected by using a high crystalline quality a-GaN. In our study, we realized a high crystalline quality a-GaN by using both patterned sapphire substrate (PSS) and sputtered AlN buffer layer (sp-AlN). The PSS had conical patterns with a diameter of 900 nm and a height of 600 nm. The patterns placed with triangular arrangement and an interval of 1000 nm. The 30-nm-thick sp-AlN was deposited on the PSS at 300 oC. Approximately 3.5-um-thick a-GaN was grown by using metal-organic vapor phase epitaxy with optimized growth conditions. The crystalline qualities of the a-GaN were evaluated by X-ray rocking curves full width at half maximum (XRC-FWHM) for both on- and off-axis planes. Moreover, the growth behavior of a-GaN on PSS was characterized by in-situ reflectance and scanning electron microscope. For the on-axis GaN (11-20) plane, the XRC-FWHM in the c-axis direction of the a-GaN was 462 arcsec, whereas it was 647 arcsec in the m-axis direction. For the off-axis GaN (10-12) plane, the XRC-FWHM was 990 arcsec. These XRC-FWHMs were significantly decreased compared with that of a-GaN grown on nitridated r-plane flat sapphire. It was suggested the density of defects in a-GaN were decreased by both PSS and sp-AlN. To clarify how to defects in a-GaN decrease by using the PSS and sp-AlN the transmission electron microscope observation was performed.

Paper Details

Date Published: 14 March 2018
Proc. SPIE 10532, Gallium Nitride Materials and Devices XIII, 105320E (14 March 2018);
Show Author Affiliations
Shunya Otsuki, Meijo Univ. (Japan)
Daiki Jinno, Meijo Univ. (Japan)
Koito Manufacturing Co., Ltd. (Japan)
Hisayoshi Daicho, Koito Manufacturing Co., Ltd. (Japan)
Satoshi Kamiyama, Meijo Univ. (Japan)
Tetsuya Takeuchi, Meijo Univ. (Japan)
Motoaki Iwaya, Meijo Univ. (Japan)
Isamu Akasaki, Meijo Univ. (Japan)
Nagoya Univ. (Japan)

Published in SPIE Proceedings Vol. 10532:
Gallium Nitride Materials and Devices XIII
Jen-Inn Chyi; Hiroshi Fujioka; Hadis Morkoç, Editor(s)

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