A GaN–SiC hybrid material for high-frequency and power electronics

We demonstrate that 3.5% in-plane lattice mismatch between GaN (0001) epitaxial layers and SiC (0001) substrates can be accommodated without triggering extended defects over large areas using a grain-boundary-free AlN nucleation layer (NL). Defect formation in the initial epitaxial growth phase is t...

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Bibliographic Details
Published in:Applied physics letters 2018-07, Vol.113 (4)
Main Authors: Chen, Jr-Tai, Bergsten, Johan, Lu, Jun, Janzén, Erik, Thorsell, Mattias, Hultman, Lars, Rorsman, Niklas, Kordina, Olof
Format: Article
Language:English
Subjects:
Aluminum gallium nitrides
Aluminum nitride
Applied physics
Breakdown
Buffer layers
Crystal defects
Electron mobility
Electronic devices
Electronics
Epitaxial growth
Epitaxial layers
Gallium nitrides
Heterostructures
High electron mobility transistors
Resonant frequencies
Semiconductor devices
Substrates
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Summary:We demonstrate that 3.5% in-plane lattice mismatch between GaN (0001) epitaxial layers and SiC (0001) substrates can be accommodated without triggering extended defects over large areas using a grain-boundary-free AlN nucleation layer (NL). Defect formation in the initial epitaxial growth phase is thus significantly alleviated, confirmed by various characterization techniques. As a result, a high-quality 0.2-μm thin GaN layer can be grown on the AlN NL and directly serve as a channel layer in power devices, like high electron mobility transistors (HEMTs). The channel electrons exhibit a state-of-the-art mobility of >2000 cm2/V-s, in the AlGaN/GaN heterostructures without a conventional thick C- or Fe-doped buffer layer. The highly scaled transistor processed on the heterostructure with a nearly perfect GaN–SiC interface shows excellent DC and microwave performances. A peak RF power density of 5.8 W/mm was obtained at VDSQ = 40 V and a fundamental frequency of 30 GHz. Moreover, an unpassivated 0.2-μm GaN/AlN/SiC stack shows lateral and vertical breakdowns at 1.5 kV. Perfecting the GaN–SiC interface enables a GaN–SiC hybrid material that combines the high-electron-velocity thin GaN with the high-breakdown bulk SiC, which promises further advances in a wide spectrum of high-frequency and power electronics.
ISSN:0003-6951
1077-3118
1077-3118
DOI:10.1063/1.5042049