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Improved AlScN/GaN heterostructures grown by metal-organic chemical vapor deposition

: Manz, Christian; Leone, Stefano; Kirste, Lutz; Ligl, Jana; Frei, Kathrin; Fuchs, Theodor; Prescher, Mario; Waltereit, Patrick; Verheijen, Marcel A.; Graff, Andreas; Simon-Najasek, Michél; Altmann, Frank; Fiederle, Michael; Ambacher, Oliver

Volltext urn:nbn:de:0011-n-6245396 (3.1 MByte PDF)
MD5 Fingerprint: 80191af9c52519fe063afcfd2900d036
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Erstellt am: 11.2.2021

Semiconductor Science and Technology 36 (2021), Nr.3, Art. 034003, 10 S.
ISSN: 0268-1242
ISSN: 1361-6641
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IAF ()
Fraunhofer IMWS ()
AlScN; ScAlN; aluminium scandium nitride; high electron mobility transistor; MOCVD; atom diffusion

AlScN/GaN epitaxial heterostructures have raised much interest in recent years, because of the high potential of such structures for high-frequency and high-power electronic applications. Compared to conventional AlGaN/GaN heterostructures, the high spontaneous and piezoelectric polarization of AlScN can yield to a five-time increase in sheet carrier density of the two-dimensional electron gas formed at the AlScN/GaN heterointerface. Very promising radio-frequency device performance has been shown on samples deposited by molecular beam epitaxy. Recently, AlScN/GaN heterostructures have been demonstrated, which were processed by the more industrial compatible growth method metal-organic chemical vapor deposition(MOCVD). In this work, SiNx passivated MOCVD-grown AlScN/GaN heterostructures with improved structural quality have been developed. Analytical transmission electron microscopy, secondary ion mass spectrometry and high-resolution x-ray diffraction analysis indicate the presence of undefined interfaces between the epitaxial layers and an uneven distribution of Aland Sc in the AlScN layer. However, AlScN-based high-electron-mobility transistors (HEMT)have been fabricated and compared with AlN/GaN HEMTs. The device characteristics of theAlScN-based HEMT are promising, showing a transconductance close to 500 mS mm−1 and a drain current above 1700 mA mm−1.