TY - JOUR
T1 - Improved AlScN/GaN heterostructures grown by metal-organic chemical vapor deposition
AU - Manz, Christian
AU - Leone, Stefano
AU - Kirste, Lutz
AU - Ligl, Jana
AU - Frei, Kathrin
AU - Fuchs, Theodor
AU - Prescher, Mario
AU - Waltereit, Patrick
AU - Verheijen, Marcel A.
AU - Graff, Andreas
AU - Simon-Najasek, Michél
AU - Altmann, Frank
AU - Fiederle, Michael
AU - Ambacher, Oliver
PY - 2021/3
Y1 - 2021/3
N2 - 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 Al and 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 the AlScN-based HEMT are promising, showing a transconductance close to 500 mS mm-1 and a drain current above 1700 mA mm-1.
AB - 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 Al and 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 the AlScN-based HEMT are promising, showing a transconductance close to 500 mS mm-1 and a drain current above 1700 mA mm-1.
KW - AlScN
KW - Aluminum scandium nitride
KW - Atom diffusion
KW - High electron mobility transistor
KW - MOCVD
KW - ScAlN
UR - http://www.scopus.com/inward/record.url?scp=85100343311&partnerID=8YFLogxK
U2 - 10.1088/1361-6641/abd924
DO - 10.1088/1361-6641/abd924
M3 - Article
AN - SCOPUS:85100343311
VL - 36
JO - Semiconductor Science and Technology
JF - Semiconductor Science and Technology
SN - 0268-1242
IS - 3
M1 - 034003
ER -