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Reliability and degradation mechanism of 0.25 µm AlGaN/GaN HEMTs under RF stress conditions

: Dammann, M.; Baeumler, M.; Gütle, F.; Cäsar, M.; Walcher, H.; Waltereit, P.; Bronner, W.; Müller, S.; Kiefer, R.; Quay, R.; Mikulla, M.; Ambacher, O.; Graff, A.; Altmann, F.; Simon, M.


Institute of Electrical and Electronics Engineers -IEEE-; IEEE Electron Devices Society; IEEE Reliability Society:
IEEE International Integrated Reliability Workshop, IRW 2011 : Final report, S. Lake Tahoe, California, USA, 16 - 20 October 2011
Piscataway/NJ: IEEE, 2011
ISBN: 978-1-4577-0113-9
International Integrated Reliability Workshop (IRW) <30, 2011, South Lake Tahoe/Calif.>
Conference Paper
Fraunhofer IAF ()
Fraunhofer IWM ()

The reliability and degradation mechanism of AlGaN/GaN single stage amplifiers after 10 GHz stress at a drain voltage of 42 V and channel temperatures above 250°C was investigated using electroluminescence (EL) imaging, infrared thermography, and TEM. The extrapolated median lifetime extracted from the Arrhenius plot is 510 5 h at a channel temperature of 200°C, and the activation energy is 1.7 eV. Intermediate measurements during stress show a strong decrease of maximum drain current and gate leakage current. Physical failure analysis of faster degrading devices using EL showed that the 8 gate finger device changes from a homogeneous distribution before stress, where all gate fingers show approximately the same EL intensity, to a highly inhomogeneous distribution after stress, where one central gate finger shows a much higher EL intensity as compared to the others. Infrared thermography shows that the finger with the highest EL intensity operates at a higher channel temperature. TEM images of one stressed device reveal a dislocation below the gate on the source side edge and the formation of a void below the gate foot as the possible root cause of the observed degradation. © 2011 IEEE.