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Influence of GaN cap on robustness of AlGaN/GaN HEMTs
P. Ivo1, A. Glowacki2, R. Pazirandeh1, E. Bahat-Treidel1, R. Lossy1, J. Würfl1, C. Boit2, G. Tränkle1
1 Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Strasse 4, 12489 Berlin, Germany
2 Institut für Hochfrequenz- und Halbleiter-Systemtechnologien, Technische Universität Berlin Berlin, Germany
Published in:
Proc. Int. Reliability Physics Symposium 2009 (IEEE), pp. 71-75 (2009).
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Abstract:
DC-Step-Stress-Tests of GaN HEMTs have been performed
on wafers with and without GaN-cap. The tests consist of
a step ramping of drain-source voltage VDS by 5V every two
hours at off-state. The irreversible evolution of leakage current
starting at a certain drain voltage has been taken as a criterion
for the onset of device degradation. It has been stated that there
is a stability limit for VDS depending on the epitaxial design. It
has been found that wafers with GaN cap show much higher
critical voltages as compared to non-capped epitaxial designs.
Electroluminescence measurements have been performed to localize
defects after DC-Step-Stress-Tests up to 80V for wafer
without GaN cap and 120V for wafer with GaN cap.
Keywords:
GaN reliability, electroluminescence, GaN cap, gate leakage current, critical voltage
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