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Proceedings Paper

Effects of Mg pre-flow, memory, and diffusion on the growth of p-GaN with MOCVD (Conference Presentation)
Author(s): Charng-Gan Tu; Hao-Tsung Chen; Sheng-Hung Chen; Chen-Yao Chao; Yean-Woei Kiang; Chih-Chung Yang
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Paper Abstract

In MOCVD growth, two key factors for growing a p-type structure, when the modulation growth or delta-doping technique is used, include Mg memory and diffusion. With high-temperature growth (>900 degree C), doped Mg can diffuse into the under-layer. Also, due to the high-pressure growth and growth chamber coating in MOCVD, plenty Mg atoms exist in the growth chamber for a duration after Mg supply is ended. In this situation, Mg doping continues in the following designated un-doped layers. In this paper, we demonstrate the study results of Mg preflow, memory, and diffusion. The results show that pre-flow of Mg into the growth chamber can lead to a significantly higher Mg doping concentration in growing a p-GaN layer. In other words, a duration for Mg buildup is required for high Mg incorporation. Based on SIMS study, we find that with the pre-flow growth, a high- and a low-doping p-GaN layer are formed. The doping concentration difference between the two layers is about 10 times. The thickness of the high- (low-) doping layer is about 40 (65) nm. The growth of the high-doping layer starts 10-15 min after Mg supply starts (Mg buildup time). The diffusion length of Mg into the AlGaN layer beneath (Mg content reduced to <5%) is about 10 nm. The memory time of Mg in the growth chamber is about 60 min, after which the Mg doping concentration is reduced to <1%.

Paper Details

Date Published: 20 April 2017
PDF: 1 pages
Proc. SPIE 10124, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXI, 101240E (20 April 2017); doi: 10.1117/12.2249540
Show Author Affiliations
Charng-Gan Tu, National Taiwan Univ. (Taiwan)
Hao-Tsung Chen, National Taiwan Univ. (Taiwan)
Sheng-Hung Chen, National Taiwan Univ. (Taiwan)
Chen-Yao Chao, National Taiwan Univ. (Taiwan)
Yean-Woei Kiang, National Taiwan Univ. (Taiwan)
Chih-Chung Yang, National Taiwan Univ. (Taiwan)

Published in SPIE Proceedings Vol. 10124:
Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXI
Jong Kyu Kim; Michael R. Krames; Li-Wei Tu; Martin Strassburg, Editor(s)

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