Fabrication of GaN Microporous Structure at a GaN/Sapphire Interface as the Template for Thick-Film GaN Separation Grown by HVPE

In this paper, a microporous structure at the GaN/sapphire interface has been obtained by an electrochemical etching method via a selective etching progress using an as-grown GaN/sapphire wafer grown by metal organic chemical vapor deposition. The as-prepared GaN interfacial microporous structure ha...

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Bibliographic Details
Published in:Journal of electronic materials 2016-10, Vol.45 (10), p.4782-4789
Main Authors: Chen, Jianli, Cheng, Hongjuan, Zhang, Song, Lan, Feifei, Qi, Chengjun, Xu, Yongkuan, Wang, Zaien, Li, Jing, Lai, Zhanping
Format: Article
Language:English
Subjects:
Characterization and Evaluation of Materials
Chemistry and Materials Science
Crystals
Electronics and Microelectronics
Etching
Gallium nitride epitaxy
Instrumentation
Materials Science
Optical and Electronic Materials
Solid State Physics
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Summary:In this paper, a microporous structure at the GaN/sapphire interface has been obtained by an electrochemical etching method via a selective etching progress using an as-grown GaN/sapphire wafer grown by metal organic chemical vapor deposition. The as-prepared GaN interfacial microporous structure has been used as a template for the following growth of thick-film GaN crystal by hydride vapor phase epitaxy (HVPE), facilitating the fabrication of a free-standing GaN substrate detached from a sapphire substrate. The evolution of the interfacial microporous structure has been investigated by varying the etching voltages and time, and the formation mechanism of interfacial microporous structure has been discussed in detail as well. Appropriate interfacial microporous structure is beneficial for separating the thick GaN crystal grown by HVPE from sapphire during the cooling down process. The separation that occurred at the place of interfacial microporous can be attributed to the large thermal strain between GaN and sapphire. This work realized the fabrication of a free-standing GaN substrate with high crystal quality and nearly no residual strain.
ISSN:0361-5235
1543-186X
DOI:10.1007/s11664-016-4726-8