What is it about?

Wide bandgap semiconductors have desirable properties for power electronic devices as they can withstand large breakdown fields. Gallium oxide is a promising ultrawide bandgap material, that can be grown in large-area substrates to allow for effective homoepitaxial growth that's required for electronic devices. However, these materials are limited by point defects that can lead to poor device stability and control. This study looks to analyse gallium oxide epilayers on commercial substrates in order to identify and characterise the electrically active point defects.

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Why is it important?

Deep Level Transient Spectroscopy is an effective technique in quantitively characterizing the electrically active point defects. This work highlights the presence of an impurity (E9) that is a deep acceptor level found in material grown via metal-organic chemical vapour deposition. It also reveals an unintentional donor level at 0.10 eV from the conduction band minimum, which contributes to auto n-type β-Ga2O3. Finally, it demonstrates that these impurities originate from either the commercial substrates or the interface between the epilayer and substrate, through profiling analysis.

Perspectives

I hope this article gives an insight into the nature of electrically active defects in β-Ga2O3, which can have a marked impact on an electronic device's performance. The origin of these impurities is still unknown but I believe this work is a step forward to identifying and out-engineering these point defects. We continue to investigate β-Ga2O3 crystals with our collaborators, with the ambition of finding the origin and nature of all the traps we observe. I would like to thank all contributing authors from both the University of Bristol and the University of Manchester.

Christopher Dawe
University of Manchester

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This page is a summary of: Deep level traps in (010) β-Ga2O3 epilayers grown by metal organic chemical vapor deposition on Sn-doped β-Ga2O3 substrates, Journal of Applied Physics, July 2024, American Institute of Physics,
DOI: 10.1063/5.0202581.
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