Abstract
In this work, a method to acquire freestanding GaN by using low temperature (LT)-GaN layer was put forward. To obtain porous structure and increase the crystallinity, LT-GaN layers were annealed at high temperature. The morphology of LT-GaN layers with different thickness and annealing temperature before and after annealing was analyzed. Comparison of GaN films using different LT-GaN layers was made to acquire optimal LT-GaN process. According to HRXRD and Raman results, GaN grown on 800 nm LT-GaN layer which was annealed at 1090 °C has good crystal quality and small stress. The GaN film was successfully separated from the substrate after cooling down. The self-separation mechanism of this method was discussed. Cross-sectional EBSD map** measurements were carried out to investigate the effect of LT-buffer layer on improvement of crystal quality and stress relief. The optical property of the obtained freestanding GaN film was also determined by PL measurement.
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Acknowledgements
This work was supported by the National Natural Science Foundation of China (Grant Nos. 51702226, 51572153 and 51602177) and the Natural Science Foundation of Shanxi Province (Grant No. 201701D221078).
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Tian, Y., Shao, Y., Hao, X. et al. Preparation and optimization of freestanding GaN using low-temperature GaN layer. Front. Mater. Sci. 13, 314–322 (2019). https://doi.org/10.1007/s11706-019-0466-z
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DOI: https://doi.org/10.1007/s11706-019-0466-z