Investigations of GaN growth on the sapphire substrate by MOCVD method with different AlN buffer deposition temperatures

The effects of different AlN buffer deposition temperatures on the GaN material properties grown on sapphire substrate was investigated. At relatively higher AlN buffer growth temperature, the surface morphology of subsequent grown GaN layer was decorated with island-like structure and revealed the...

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Bibliographic Details
Published in:Materials science in semiconductor processing 2016-04, Vol.45, p.1-8
Main Authors: Huang, Wei-Ching, Chu, Chung-Ming, Wong, Yuen-Yee, Chen, Kai-Wei, Lin, Yen-Ku, Wu, Chia-Hsun, Lee, Wei-I, Chang, Edward-Yi
Format: Article
Language:English
Subjects:
AlN buffer
Aluminum nitride
Buffer layers
Buffers
Deposition
Gallium nitrides
GaN
MOCVD
Sapphire
Semiconductors
Substrates
temperature
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Summary:The effects of different AlN buffer deposition temperatures on the GaN material properties grown on sapphire substrate was investigated. At relatively higher AlN buffer growth temperature, the surface morphology of subsequent grown GaN layer was decorated with island-like structure and revealed the mixed-polarity characteristics. In addition, the density of screw TD and leakage current in the GaN film was also increased. The occurrence of mixed-polarity GaN material result could be from unintentional nitridation of the sapphire substrate by ammonia (NH3) precursor at the beginning of the AlN buffer layer growth. By using two-step temperature growth process for the buffer layer, the unintentional nitridation could be effectively suppressed. The GaN film grown on this buffer layer exhibited a smooth surface, single polarity, high crystalline quality and high resistivity. AlGaN/GaN high electron-mobility transistor (HEMT) devices were also successfully fabricated by using the two-step AlN buffer layer.
ISSN:1369-8001
1873-4081
DOI:10.1016/j.mssp.2016.01.008